Physics Form 4 Module

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CHAPTER 1: INTRODUCTION TO PHYSICS

1.1 Understanding Physics

explain what physics is

recognize the physics in everyday objects and natural phenomena

1. A phenomenon is an that can be perceived by our.2. In physics, we study . , such as the eruption of volcano, rain fall,

formation of rainbow and the . of matter, such as length, temperature and volume.

3. There are many fields of study in physics, including ., .., , .., ,

, ., .. and .

1.2 Understanding Base Quantities and Derived Quantities

explain what base quantities and derived quantities are

list base quantities and their units

list some derived quantities and their units.

express quantities using prefixes.

express quantities using scientific notation

express derived quantities as well as their units in terms of base quantities and base units.

solve problems involving conversion of units

1. A physical quantity is a ..that can be

2. Base quantities are . . that cannot be defined in terms of

other ....

There are base quantities:.., ., .,

and ..

Physical Quantity Base S.I. Unit

Base Quantity Quantity Symbol S.I. Unit Unit symbol

Length

Mass

Time

Electric Current

Temperature

3. Derived quantities are. . consisting of combinations

of ..., by , , or both operations.

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4. Derived quantities as well as their units are expressed in terms of base quantities and base S.I. unitsas follows:

Given that l: length, m : mass, t: time, I: electric current, T: temperature.Derived quantities

(symbol)Expressed in base quantities Derived units

Area

(A)

Volume(V)

Density

( )

Speed

(v)

Work or Energy

(W or E)

Power

(P)

Velocity

(v) v = t

lUnit v =

s

m

= 1sm(read as metre per second)

Acceleration

(a) a = t

u-v

u = initial velocity

v = final velocity

t = time taken

Unit a =s

ms1

= 2sm(read as metre per second per second)

Force

(F)

F = ma

m = massa = acceleration

Unit F = kg x 2sm

= kg 2sm= N

(read as newton)

Impulse(Ft)

Ft = change of momentum= mv mu

m = mass

u = initial velocity

v = final velocity

Unit Ft = kg x 1sm

= kg 1sm = N s

(read as newton second)

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Momentum

(p)

p = mv

m = mass

v = velocity

Unit p = kg x 1ms= kg 1sm = N s

(read as newton second)

Pressure

(P) P =

A

F

F = forceA = area

Unit P =2

m

N

= 2mN= Pa

(read as pascal)Specific heat

capacity

(c)

c =m

Q

Q = heat energy

m = mass

= change in temperature

Unit c =Ckg

Jo

= 101 CkgJ

=kgK

J

= 11 KkgJ(read as joule per kilogram per kelvin)

Frequency(f) f = T

1

T = period of swing; unit:

second (s)

Unit f =s

1

= 1s= Hz

(read as hertz)Electrical charges

(Q)Q = ItI = electric current

t = time

Unit Q = A s= C

(read as coulomb)

Resistance(R) R = I

V

V = voltage; unit: volt (V)

I = electric current

Unit R =A

V

= 1AV=

(read as ohm)

5. Prefixes are used to express some physical quantities that are either very big or very small.

Prefix Symbol Value Prefix Symbol Value

piko deci

nano kilo

micro mega

milli giga

centi tera

6. Standard form or scientific notation:A x 10n where 1 A < 10, n is an integer (integer positive or negative)

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Physical

QuantityValue

Standard form or Scientific

notation

Mass of earth 6 020 000 000 000 000 000 000 000 kg

Diameter of an oilmolecule

0. 000 000 000 74 m

Speed or light inthe vacuum 299 792 458 m s-1

Radius of earth 6 370 000 m

Mass of hydrogenatom

0. 000 021 kg

Time of a day 86 400 s

Temperature of thecentre of the earth

6 000 000 K

Size of a flu virus 0.000 000 2 m

1.3 Understanding Scalar and Vector Quantities

define scalar and vector quantities

give examples of scalar and vector quantities.

1. Scalar quantities are quantities that have . but no ..

2. Vector quantities are quantities that have both and .

Scalar Quantities Vector Quantities

3. Example:

Distance(s) Displacement(s)

Total . of

the.

Distance between ..

measured along a specific direction .. quantity .. quantity

Speed Velocity Rate of of Rate of of ..

Speed = Velocity =

quantity . quantity

4. Annie the ant is traveling down the road to buy an umbrella for these rainy days. She walks from hernest, A to B, B to C in 10 minutes time as shown in the picture below:

(a) What is the distance she traveled?(b) What is her displacement from A?(c) What is her speed?

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(d) What is her velocity?

Solution:

(a) Distance traveled =

=

= .

(b) Displacement of the object from A = 5 m towards the direction of AC

tan =

=

= . o

The displacement of the ant is .. in the direction of from ...

(c) Speed =

=

(d) Velocity =

= towards the direction of ..

1.4 Measuring Instruments

Measure physical quantities using appropriate instruments

Explain accuracy and consistency

Explain sensitivity

Explain types of experimental error

5

A

BC4 m 3 m

Annie the antU


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Use appropriate techniques to reduce errors

Accuracy, Consistency and Sensitivity in measurement & ErrorsDefinitions:

1. Consistency in measurements refers to .. . there is among the measurements

made when a quantity is measured ..

2. Accuracy of a measurement is .. the measurement made is to the ..

of the quantity.

3. Sensitivity of an instrument is its . to detect a in the quantity to be

measured in a .. .. of .

4. Figure 1.4.1 shows the result for four shooters A, B, C and D in a tournament. Every shooter shot five

times.

5. Error is . caused by measuring or the .. or the .

. of the surroundings.

6. Two main types of errors : . . and .

Parallax errors

Definition:

A parallax error is an in reading an instrument because the observers eyes and pointer are not

.. to the plane of the scale.

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Shooter Consistency AccuracyA

B

C

D

Systematic Error Random Error Caused by:

i. Error in instrumentsii. Error in calibration

Caused by:i. Surroundings factors, such as

temperature and windii. Carelessness of the observer

Examplei. .

Examplei. ..ii. Error in .

.. be reduced or overcome . be reduced Way of correction

i. Take the error into account Ways of correction

i. Take several readings and calculatethe average value.


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Concept & Explanation:

1. Figure 2, 3 and 4 show the correct positioning of the observers eyes to avoid parallax errors.

2. How to avoid parallax error?

(a) position of eyes must bewith the scale of the reading to be taken.

(b) When taking reading from an ammeter, we must make sure that the eyes are exactly in front of the

pointer, so that the of the pointer in the mirror is . .the pointer. In other words, the reflection of the pointer on the mirror could not be seen by the

observer, then it is free from ..

Measuring Instruments & Accuracy

Measuring Instruments:

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Physical Quantity Measuring Instruments

Length

Current

Mass

Temperature

Time

Voltage


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(A) Instruments measuring length1. Metre Rule

2. Vernier CalipersThe same wire is measured by a vernier caliper. The reading is as follows:

Figure 6

3. Micrometer Screw GaugeThe diameter of the wire is measured by a micrometer screw gauge. The reading is as follows:

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Ruler A Ruler BSensitivityAccuracyLength of wire

SensitivityAccuracyLength of wire

4 5

0 5 10

20

250 5

wire

2 3 4 510Ruler A

2 3 4 50 1Ruler B


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Vernier Calipers

Positive zero error Negative zero error

Figure 9Positive zero error = + 0.08 cmAll measurements taken with this vernier calipersmust be corrected by subtracting 0.08 cm from thereadings.

Figure 10Negative zero error = - ( 0.1 0.08 ) cm

= - 0.02 cmAll measurements taken with this vernier calipersmust be corrected by subtracting - 0.08 cm, whichis adding 0.08 cm to the readings

Eample Example

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SensitivityAccuracyDiameter ofwire

1) How to read from a vernier caliper?

Figure 8 shows the use of a vernier caliper tomeasure the size of the inner diameter of abeaker.Inner diameter= main scale reading + vernier scale reading= 3.2 + 0.04= 3.24 cm


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(i) Figure 11 (ii)Zero error = + 0.04 cmVernier caliper reading = 0.4 + 0.01

= 0.41 cmCorrected reading= vernier caliper reading zero error= 0.41 0.04= 0.37 cm

(i) Figure 12 (ii)Zero error = -(0.1 0.07) cm

= - 0.03 cmVernier caliper reading = 3.6 + 0.02

= 3.62 cmCorrected reading= vernier caliper reading zero error= 3.62 (-0.03)= 3.62 + 0.03= 3.65 cm

Exercise:1 Write down the readings shown by the following

(a)

(b)

(c)

(d)

2. (a) The following diagram shows the scale of a vernier calliper when the jaws are closed.

10

0 5 10

0 1

0 5 10

6 7

0 5 10

7 8

0 5 10

0 1

Answer: ..

Answer: ..

Answer: ..

Answer: ..

0 5 10

4 5A B

QP


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Zero error =

(b) The following diagram shows the scale of the same vernier calliper when there are 40 pieces ofcardboard between the jaws.

Micrometer Screw Gauge

1. How to read from a micrometer screw gauge?Figure 13 shows the use of a micrometer screw gauge to measure the size of a spherical object.

11

0 5 10

5 6

Reading shown =

Corrected reading = =


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Main scale reading = 5.5 mmThimble scale reading = 12 x 0.01

= 0.12 mmFinal reading = 5.5 + 0.12

= 5.62 mm2. Positive zero error and negative zero error

Positive zero error Negative zero error

Positive zero error = + 0.04 mmAll measurements taken with this micrometer screwgauge must be corrected by subtracting 0.04 mm fromthe readings

Negative zero error = - 0.04 mmAll measurements taken with this micrometer screwgauge must be corrected by subtracting - 0.04 mm,which is adding 0.04 mm from the readings

Example

Zero error = + 0.01 mmmicrometer screw gauge reading= 2.5 + 0.35= 2.85 mm

Corrected reading= micrometer screw gauge reading zero error= 2.85 0.01= 2.84 mm

Example

Zero error = - 0.03 mmmicrometer screw gauge reading= 6.0 + 0.08= 6.08 mm

Corrected reading= micrometer screw gauge reading zero error= 6.08 (-0.03)= 6.08 + 0.03= 6.11 mm

Exercise:1. Write down the readings shown by the following micrometer screw gauges.

(a) (b)

Answer: . Answer:..

(c) (d)

12

25

300 5

40

5 10 1545

30

350 5

5

100


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Answer: Answer:.

2. (a) Determine the readings of the following micrometer screw gauges.

Zero error = .. mm Zero error = ........ mm

(b) Determine the readings of the following micrometer screw gauges.

(B) Instrument Measuring Current : Ammeter

Ammeter ranged .Sensitivity =.Accuracy =.

Doubled ranged ammeterUpper scale ranged

13

0 0

45

5

0

0

5

0

0 0 5

15

20

Zero error = Reading shown = ..=

Corrected reading =..= .


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Sensitivity =; accuracy =..Lower scale rangedSensitivity = accuracy =Reading =..

Miliammeter..Sensitivity =Accuracy = Reading =..

(C) Instrument Measuring Temperature:Thermometer Accuracy = ..

(D) InstrumentMeasuring Time

Mechanical StopwatchAccuracy =..Reading =

1.5 Scientific Investigation

Identify variables in a given situation

Identify a queation suitable for scientific investigation

Form a hypothesis

Design and carry out a simple experiment to test the hypothesis

Record and present data in a suitable form

Interpret data to draw a conclusion

Write a report of the investigation

Clone of SPM Try Exam of the Perak State year 2003: Paper 3 / Section B/ Question 2Notes: MV -manipulated variable; RV-responding variable; C- constant

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Digital StopwatchAccuracy =Reading = ..


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Two twin brothers, Micheal and Jackson, of the same size, are swinging happily on the swings at aplayground as shown in the figure above.

However, the ropes that is holding the swing where Micheal is sitting is longer than Jacksons. And, Michealnotices that his swing is swinging slower than his brother, Jackson.Using this information;(a) make a suitable inference, [1 mark](b) state one appropriate hypothesis that could be investigated, [1 mark](c) describe how you would design an experiment to test your hypothesis using a bob, strings and other

apparatus.In your description, state clearly the following:(i) aim of the experiment(ii) variables in the experiment(iii) list of apparatus and materials(iv) arrangement of the apparatus(v) the procedure of the experiment, which includes the method of controlling the manipulated

variable and the method of measuring the responding variable.

(vi) the way you would tabulate the data(vii) the way you would analyze the data [10 marks]

Answer:(a) Inference: . influences .

(b) Hypothesis: When the increases, the increases.

(c)

Marks1st mark/

1

AimTo investigate the relationship between ..

and .2nd mark/2

MV: RV:

3rd mark/3

C

4th mark/4

List ofapparatus &materials

, ............., bob, string, retort stand and clamp, split cork.

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Keywords to indicatethe must-use-apparatus and hinting

on the Pendulum

experiment

Keywords toindicate C ismass

Keywords toindicate MV islength

Keywords toindicate RV istime of making a

complete swing


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5th mark/5

Arrangementof apparatus

6th mark/6

Method tocontrol MV Measure by using a ..

(Notes: Active or passive sentences are acceptable. Must have a value +measuring instrument)

7th mark/7

Method tocontrol RV

Measure .. by using a

Calculate period of a swing, T as follows: ..

8th mark/8

Repetition : Repeat the experiment with l= ..using the same

9th mark /

9 : Tabulate data 10th mark /10 : Analyze data

Plot graph ..against

CHAPTER 2: FORCES AND MOTION

2.1 Linear Motion

Define distance and displacement

Define speed and velocity and state that v = s/t

Define acceleration and deceleration and state that a = v - u

t

Calculate speed and velocity

Calculate acceleration / deceleration

Solve problems on linear motion with uniform acceleration using

(i) v = u + at

(ii) s = ut + at2

(iii) v2 = u2 + 2as

Distance and Displacement

16

.


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A: Fill in the blank with the correct answer

1. Physical quantities can be divided into 2 :

(a) quantity

(b) quantity

2. Distance is quantity which has . and no

3. is a vector quantity which has magnitude and direction

4. The SI unit for both physical quantities is ..

B: Complete the table below :

Aspect Distance Displacement

Definition Distance taken with consideration of direction

Type of quantity Scalar quantity

SI unit

Speed and Velocity

C: Complete the table below

Aspect Speed Velocity

Definition Rate of change of displacementType of physicalquantity

Scalar

FormulaSpeed= Total distance

Time

Velocity=

SI unit m s-1

Symbol

u, v

u denotes initial speedv denotes final speedAverage speed

= Total distanceTime

u, v

u denotes initial velocityv denotes final velocityWe usually consider the forward motion ( tothe right ) as positive and the backward ( to theleft) as negative )

Acceleration

D: Fill in the blank with the correct answer.

1. Acceleration is the rate of change of ..

2. Acceleration , a = Final velocity - Initial velocityTime taken

3. The SI unit of acceleration is .

4. Acceleration is a .. quantity

5. occurs when an object moves with . velocity.

6. . occurs when an object moves with velocity

17

a =


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E: Solve the problem.

1. A car starts from points from point O and moves to U, 50 m to the north in 60 s. The car then

moves to B, 120 m to the west in 40 s. Finally, it stops.

Calculate the :

(a) total distance moved by the car

(b) displacement of the car

(c) speed of the car when it is moves to the north

(d) velocity of the car

(e) average speed of the car

2. A bus stops at a station to pick passengers up. It then moves and attains a velocity of 15 m s-1 in 8s. What is the acceleration of the bus ?

F. Complete the table below with the correct answer

Increasing short increasing far same

Speed decreasing low high decreasing

Pattern Explanation

(a) Direction of motion

Initial Final

The distance between the dots is the . It shows that the objectis moving with

(b) Direction of motion The distance between the dots is .. It shows that the objectis moving very .

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. . . . . . .

. . . . . . . . . . . . . . . .


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Initial Final(c) Direction of motion

Initial Final

The distance between the dots is . It shows that the speedof the object is moving with .

(d) Direction of motion

Initial Final

The distance between the dots is . It shows that thespeed of the object is .

(e) Direction of motion

Initial Final

The distance between the dots is . It shows that thespeed of the object is

G: Determine the acceleration of a trolley from the ticker tape

1. The ticker tape is divided into 5 parts. Every part has 2 ticks as shown in figure below.

Find the acceleration.

1 cm 5 cm

A B C D E F

Solution :

Step Solution

1. Time taken of one part One part = . Ticks= . x 0.02 s= . S

19

. . . . . . .

. . . . . . .

. . . . . .


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2. initial velocity, u = s initialtinitial

u = cms

= . cm s-1

3. Final velocity, v = s finaltfinal

v = cms

= . cm s-1

4. Determine the total time

Total time = ( Total parts 1) x time of one part

Total time, t= ( ) x .. s

= x ... s

= . S5. Acceleration, a = v u

t a = v u

t

== cm s-2

The equations of motion

1. Complete the table below

Physical Quantity SymbolDisplacement

v

Initial velocityacceleration

2. List the equations of linear motion.

(i)

(ii)

(iii)(iv)

Questions

1. Solve the following problems using the equations of linear motion(a) A car moves from rest to a velocity of 10 ms-1 in 5 s .Calculate the acceleration of the car

Solution :

(b) A car traveling with a velocity of 10 m s-1 accelerates uniformly at a rate of 3 m s-2 for 20 s.Calculate the displacement of the car.

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Solution :

(c) A van that is traveling with velocity 16 m s-1 decelerates until it comes to a stop. If the distancetraveled is 8 m, calculate the deceleration of the van.Solution:

2.2 Analysing Motion Graph

Plot and interpret displacement-time and velocity-time graphs

Deduce from the shape of a displacement-time graph when a body is:

i) at rest

ii) moving with uniform velocity

iii) moving with non-uniform velocity

Determine distance, displacement and velocity from a displacement-time graph

Deduce from the shape of a velocity-time graph when a body is:i) at rest

ii) moving with uniform velocity

iii) moving with uniform acceleration

Determine distance, displacement and velocity and acceleration from a velocity-time graph

Solve problems on linear motion with uniform acceleration

A: Describe the motion of an object as shown in the following motion graphs.

(a) The Displacement-Time Graph

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Graph ofs against t Explanation

s/m

0 t/s

The displacement of the object from a fixed point is

.. Therefore, the velocity of the object is

.

s/m

0 t/s

The gradient of the graph = ..of the object.

The gradient of the graph is ., therefore the

velocity of the object is .

s/m

0 t/s

The gradient of the graph .. with time.

Therefore the velocity of the object . with

.

(b) The velocity time graph

Graph ofv against t Explanation

v/m s-1

t/s

Velocity of object is . . The object is

v/m s-1

The object is moving with uniform

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v/m s-1

t/s

B C

D

t/sv/m s-1

t/s

The gradient of the graph =

The gradient of the graph is

Therefore, the acceleration of the object is

v/m s-1

t/s

Area under the graph = .

B. Describe the motion of a runner who is running in a straight lines/m

t/s O t/s

5 10 12 15Solution :

C: Study the velocity-time graph.

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Motion of the runnerO - A Running with a uniform velocity of 3 m s-1

A-BB - CC - D

20

25

15

10

5

A B

D

C

10

5


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A 5 10 15 20 25

Calculate:-(i) the acceleration, a, for sections AB, BC and CD

(ii) total displacement

2.3 Understanding Inertia Explain what inertia is Relate mass to inertia Give examples to reduce the negative effects of inertia

A. Fill in the blanks or underline the correct answers

1.

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When the bus stops suddenly our feet are brought to rest but due to inertia, our body

tends to continue its (forward/backward) motion. This causes our body to jerk

forward.(thrown forward)

2.

When the bus moves suddenly from rest our feet are carried (forward/backward) but

Due to inertia our body tends to keep us (rest/moving) . This causes our body to

fall backwards. (thrown backbards)

3. The inertia of an object is the.................................. of the object to remain at ...........

or if ...................... to continue its uniform motion in a straight line

4. The mass of an object is the amount or quantity of matter contained in the object.

5. The SI unit of mass is ..

6. The mass of an object is wherever it is measured. It is different from

.. which is affected by the . of gravity.

7. An object with a larger mass has a .. Inertia.

Effects of inertia

B. Explain the positive effect by using the clues given.

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Clue : Pour our Tomato saucesClue : Drying a wet umbrella


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C .Match the correct explanation to each of the characteristics

Characteristic Explanation

(a) The tank which carries liquid in alorry should be divided into smallertanks

Hold the passengers to their seat duringcollision

(b) the part between the drivers seat and loadshould have strong steel structure Prevent the driver from hitting thesteering in an accident(c) Safety belts Prevent the load from being thrown to

the front(d) Airbag To reduce the effects of inertia when

stopped suddenly.

2.4 Analysing Momentum

Define the momentum of an object

Define momentum(p) as the product of mass (m) and velocity(v) ie p=mv

State the principle of conservation of momentum

Describe the applications of conservation of momentum

Solve problems involving momentum

A. Fill in the blank with the correct answer

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Positive effectOf inertia

Clue: Running zig-zig whenchased by a bull.Clue : Tighten the Hammer

head


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1. Momentum is defined as the product of and .

2. The formula of momentum is given by :

Momentum = .. x .

p = .

3. Momentum is a .. quantity

4. The SI unit of momentum is

5. Momentum .. when velocity ..

6. The principle of conservation of momentum states that the total momentum in a

closed of object is ..

7. The total momentum the collision is to the total momentum

after the collision, if no . acts on the system.

8. The principle of conservation of momentum can be applied in

(a) collision

(b) collision

(c) .

B. Fill in the blank

1. Collision I : Both bodies separates after collision. Momentum is ...

Before collision after collision

Momentum :

2. Collision II : Both objects move together after collision. . Is conserved.

27

m1m2 m1

m2

u2 v2

u1

m1m2 m1 + m2

u2 = 0

u1v


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Before collision after collision

Momentum :

3. Explosion : Two or more bodies in contact will be after the explosion

Before explosion after explosion

Momentum :

B. Complete the table below

Elastic collision Inelastic collision Explosion

(a) Both bodies will separate

after collision

Two or more bodies in contact will

be separated after the collision(b) The total momentum is

conserved

The total momentum is conserved

(c) The total kinetic energy

is conserved

(c) Total energy is conserved Total energy is conserved

C. Solve the following problems

1. Car A of mass 100 kg traveling at 30 m s-1 collides with Car B of mass 90 kg traveling at 20 m s-1 infront of it. Car A and B move separately after collision. If Car A moves at 25 m s-1 after collision,determine the velocity of Car B after collision.Solution :

28

(m1 + m2), u = 0 v1m2

v2


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2 : A trolley of mass 4 kg moves at 3 m s-1 and collide with a trolley of mass 2 kg which is moving in theopposite direction at 1 m s-1. After the collision, both trolleys move together with the same velocity.What is their common velocity ?Solution :

3 : A bullet of mass 2 g is shot from a gun of mass 1 kg with a velocity of 150 m s-1 . Calculatethe velocity of the recoil of the gun after firing.Solution :

2.5 Understanding the Effects of a force

describe the effects of balanced forces acting on an object

describe the effects of unbalanced forces acting on an object

determine the relationship between force, mass and acceleration i.e F=ma

Solve problems using F = ma

1. Answer the following questions.

(a) What are the effects of a force when acting on an object?

A force can.

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(i)__________ a stationary object

(ii) __________ a moving object

(iii) change the ________ / ________ of an object

(iv) change the ________ / ________ of an object

(b) Force is a ( scalar / vector ) quantity .

(c) What is the SI unit for force?

The S.I. unit for force is ____________ .

2. Fill in the blanks with appropriate answers for balanced and unbalanced forces.

(a) Forces acting on an object are said balanced when the net force is ___________.

(b) When the forces acting on an object are balanced, it is either at ___________ or moving with

___________ _____________.

(c) An object will ____________________ if the forces acting on it are not balanced.

3. Draw the graph and state the relationship between acceleration, a, force,Fand mass, m.

(i)

(m is constant) (F is constant)(ii) Relationship :

a is _________________ to F

Relationship :

a is __________________ to m

(iii) Combine the relationship:

F = k ; k is constant (k = 1)

F =

(b) The relationship betweenF, m and a is known as Newtons _____________ law of ____________.

4. Solve the following.

(a) A force, F is required to move an object of mass 1000 kg with an acceleration of 3 m s-2. Calculate Fwhen(i) object is on a smooth surface

30

a a

a

F

a

F

a

m

1

FF

a =a = 3 m s-2

m =m = 1000 kgkg


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(ii) object is on a surface where the frictional force is 200 NSolution :

(i)

(ii)

(b) A block of mass 20 kg is pulled along the ground by a force, F of 60 N. The frictional force is 10 N.Calculate the acceleration of the block.

Solution:

(c) A car of mass 1200 kg which is travelling at 90 km h-1 comes to a stop in a distance of 50 m when thebrakes are applied. What is the average braking force of the car?

2.6 Analysing Impulse and Impulsive Force

Explain what an impulsive force is

Give examples of situations involving impulsive forces

Define impulse as a change of momentum ie Ft = mv-mu

Define impulsive force as the rate of change of momentum in a collision or explosion i.e F = mv-mu

t

Explain the effect of increasing or decreasing time of impact on the magnitude of the impulsive force

Describe situations where an impulsive force needs to be reduced and suggest ways to reduce it

Describe situations where an impulsive force is beneficial

31

F


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Solve problems involving impulsive forces

1. Define impulse and impulsive force by completing the following table.

Situation Explanation

A ball of mass, m is kicked witha force,F. The time of contact ist. The ball accelerates from u tov.

From : F = ma

F = m

F =t

mv mu = change of

Impulsive force

F t1

F mumv

F =t

t

mumv=

Impulsive force is defined as the .........................

. in a collision orexplosion.

Impulse= force x time

Impulse = Ft =

= change of ..

SI unit for impulse is or ..

2.

(i) Fill in the blanks with appropriate answers.

Impulsive force is a force which acts over a very .. time interval during

.. and .

(ii) By using the figures given, determine whether the impulsive force acting is large or small.

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3. Two eggs of the same mass are released from the same height, as shown in the figure below. EggA falls ona concrete floor while eggB falls on a thick folded towel.

Using Figure A and Figure B, compare the conditions of the eggs after the fall and explain the relationshipbetween the material where the eggs landed and the force acting on the eggs upon landing.

4. A tennis ball of mass 45 g travels at a velocity of 70 m s1 immediately after it is struck by a racket.

The time of contact between the tennis ball and the racket is 0.5 ms. Calculate(a) impulse and(b) impulsive force exerted on the ball.Solution :

2.7 Being Aware of the Need for Safety Features in Vehicles

Describe the importance of safety features in vehicles

33

Figure A Figure B

Automatic air__________

Head______

Reinforced passenger compartment

Crumple zones

Safety seat________

Padded___________


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Safety features Importance

Padded dashboard To cushion an impact and increases the ______ __________ of collision sothe __________ _______ produced is thereby reduced

Head rest

To prevent the windscreen from shattering.

Automatic air bag

Safety seat belt

To minimize the force acting from a side- on collision.

Anti-lock braking system

To increase the time interval of impact so that the resultant impulsive force is

reduced.

2.8 Understanding Gravity

Explain acceleration due to gravity

State what a gravitational field is

Define gravitational field strength

Determine the value of acceleration due to gravity

Define weight (W) as the product of mass (m) and acceleration due to gravity (g) i.e W=mg

34

________________________(ABS)

Shatter proof___________

Side impact bars


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Solve problems involving acceleration due to gravity

1. Complete the following by fill in the appropriate answer.

a. An object will .. to the surface of the earth because it is pulled by

..

b. The pull or force of gravity also known as ...c. When an object falls without encountering any resistance and under the force of . only, the

object is said to be .

d. All objects freely with the same

acceleration regardless of their and

e. The constant .. of objects falling freely due

to the force of .. is known as

, g.

f. Practically, a free . can only take place in

. where there is no air resistance.

g. The region around the earth is the . fieldof the earth.

h. The gravitational field strength is defined asthe . acting on a 1 kg

mass.

i. When an object falling freely, acceleration due to gravity, g =

An object at the surface of the earth experiences gravitational force, g = .

2. State the differences between weight and mass in the table below.

Weight Mass

1. the gravitational force act on the object.

2.

3. vector quantity

4.

5. SI unit : Newton (N)

1.

2. constant quantity everywhere

3.

4. base quantity, mass = m

5.

Solve the problem below

35

vacuum

stone

feather


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3. A coconut falls from rest and hit the ground after 1.2 s.(a) What is the velocity of the coconut just before hits the

ground?(b) Calculate the height of the coconut before it fall.

4. A stone is thrown vertically upwards with a velocity of 20 m s-1. If g = 10 ms-2, calculate(a) the maximum height reached(b) the time taken for the stone to return to its original position.

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2.9 Analysing Forces in Equilibrium

Describe situations where forces are in equilibrium

State what a resultant force is

Add two forces to determine the resultant force

Resolve a force into the effective component forces

Solve problems involving forces in equilibrium

1. Fill in the blanks.i) Forces that act on an object are said to be in .. when the object is .

or is moving at .

ii) The net force that acts on an object when two or more forces act on it is known as the

....

iii) When . is reached, the resultant force acting on the object is

iv) Newtons . law of motion states that to every . there is an equal but opposite

..

v) A force can be resolved into component which are to one another.

Horizontal cpmponent Fx =

Vertical componentFy =

2. In the table below, mark and label all the forces that act on the object.

i) A box is at rest on a table. ii) An object that is suspended by a rope.

iii) An airplane flying at a constant velocity. iv) A trolley being pushed at a constant velocity

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v)

Solution :

A box of mass 4 kg is being pulled by a force of 60 N at an angleof 30 0 to the surface of a floor. Calculate(a) the componentof the force which causes the box to moveforward.(b) the acceleration of the box if the frictional force between thefloor and the box is 5 N,

vi) A man pushes a box of mass 40 kg is up an inclined plane. Theinclined plane makes an angle of 30 0 with the horizontal floor. Thefrictional force acting between the inclined plane and the box is120 N. If the man pushes the box with a force of 400 N, calculatethe acceleration of the box.

vii)

Solution :

A 4 kg trolley is connected by a rope to a load of mass 6 kg. Thefriction between the table and the trolley is 15 N. The load is thenreleased. Assuming that the pulley is smooth and the rope is ofnegligible mass, find(a) the resultant force that act on the system(b) the acceleration of the system(c) the tension of the rope

38

6 kg

4 kg Smooth pulley

30 0

60 N

4 kg


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viii) Two loads of mass 3 kg and 5 kg are connected by a rope whichpasses through a smooth pulley. If the system is released from rest,calculate the acceleration of the 5 kg load.Solution :

3. Forces in equilibriumi A block of mass 6 kg is suspended vertically by a string tied at O

to the string AOB. If the system is in equilibrium, draw a vectordiagram (triangle of forces) and hence determine the tension ofstring OA and OB.

ii) A lamp of mass 1.5 kg is hung from a beam as shown in thediagram. Calculate the tension in the rope.Solution:

39

3 kg

5 kg

30 0A

O B

6 kg

1.5 kg


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2.10 Understanding Work, Energy, Power and Efficency

Explain the process of define work (W) as the product of an applied force (F) and displacement (s)

of an object in the direction of the applied force ie W = Fs

State that when work is done energy is transferred from one object to another

Define kinetic energy and state that Ek = mv2

Define gravitational potential energy and state that Ep = mgh

State the principle of conservation of energy

Define power and state that P=W/t

Explain what efficiency of a device is

Solve problems involving work, energy, power and efficiency

SECTION A. Choose the correct word in the bracket.

1

.

Work is the product of applied force and (distance/displacement) in the direction of the applied force.

2

.

When the work is done (force/energy) is transferred from one object to another.

3

.

The work done is equal to the amount of (temperature/energy) transferred.

4

.

The SI unit for work is (joule/watt).

SECTION B. Fill in the blank with the correct answer.

postion unchanged energy motion

1. Kinetic energy is the energy of an object due to its____________

2. Gravitational potential energy is the energy of an object due to its____________ in thegravitational field.

3. The principle of conservation of energy states that_________can be transferred from one form to

another but it cannot be created or destroyed.4. The principle of conservation of energy explains that the total amount of energy always remains

___________.SECTION C. State or false for each of the following statements.

1. Power is the rate of doing work (True/False)2. The efficiency of a device is the percentage of the energy input that is transformed

into useful energy.

(True/False)

SECTION D : State the transformation of energy..

Light energy Gravitational potential energy Sound energy Elastic potential energy

Statement From To

1. Durian falls to the ground Kinetic energy + sound energy2. A bulb connected to a dry cell lights up Electrical energy heat energy +3. A bell rings when the switch is pressed Electrical energy4. The motion of an arrow when an archer

releases the string

Kinetic energy + sound energy

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SECTION E : Answer all questions.

Work done

Force and displacement in the same direction Force and displacement in difference direction

W = F.s W = Work

F =___________

s = ___________

W = FX. s

W = __________ W = work

F = force

s = displacement

= angle between ______

and _____________

Diagram (a) Diagram (b)

1. Diagrams (a) and (b) shows a boy pushing a load and a weightlifter lifting aload of 60 kga) Calculate the work done

i. by the boy

ii. by the weightlifter in lifting the load.

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F

s

Fx

F

Fx

FY FYF


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2. Azman is pulling a box with a force of 50 N at an angle of 60o from the horizontal.Calculate the work done to move the box to a distance of 3 m.

3. Samyreleasing 2 kg metal ball from a building of 40 m height (Take the accelerationdue to gravity as 10 ms-2)

a) At the height of 40 m, the metal ball has (gravitationalpotential energy/kinetic energy)

b) Just before the metal ball hits the ground, the maximumenergy that it has is (gravitational potential energy/kinetic

energy).c) Calculatei) The energy of the metal ball at the height of40 m.

ii) the kinetic energy of the metal before it hits the ground.

d) What is the principle used in c ii)?

5. A motor lifting a weight 1 kg to a height of 4.0 m in 4 s. The input energy supply to the motor in onesecond is 20 J. Calculatea) power of the motor

42

Displacement = 3 m

Metal ball

40 meter


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b) the efficiency of the motor

2.11 Appreciating the Importance of Maximizing the Efficiency of Devices

Recognize the importance of maximizing efficiency of devices in conserving resources

A. Fill in the box with the correct terms.

Kinetic Friction in engine Resistance in electrolyteResistance Electrical Chemical

Light Heat

Device Conversion of energy Loss of energy Loss of energy due to

Bulb Electrical ____________ Heat __________________

Petrol engine Chemical ____________

+___________Heat and sound

__________________

__________________

Electric fan _________ Kinetic ________________Resistance in coil +

bearing

Battery _________

_

Electrical Heat__________________

__________________

B. Underline the correct statement below.

Statement Answer

1. Most of the energy in mechanical devices loss as heat and sound.(True/False)

2. A major cause of inefficiency in machines is due to friction.(True/False)

3. The output energy of devices always more then input energy. (True/False)

4. Maximizing the efficiency of devices makes the best use of the inputenergy and reduces energy wastage.

(True/False)

5. Maximizing the efficiency of devices helps to conserve energy resources.(True/False)

6. When energy transformations take place, not all of energy is used to douseful work.

(True/False)

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2.12 Understanding Elasticity

Define elasticity

Define Hookes Law

Define elastic potential energy and state that Ep = kx2

Determine the factors that affect elasticity

Describe applications of elasticity

Solve problems involving elasticity

SECTION A : Fill in the blanks with the correct word or terms.extension Force constant work energy transferredElastic limit elastic potential energy Car spring support elasticity

A cushion directly proportional Spring balance

1. The property of materials that can return to its original shape or size when the external force no longer

acts on it is known as ______________.

___________ of a spring is the maximum force that can be applied to a spring such that the spring will be

able to be restored to its original length when the force is removed.

3. Hookes Law states that the extension of a spring is ________________to applied force provided

that the elastic limit is not exceeded.

F = k x

Where F = Force on the spring

k = ________________spring

x = ______________of the spring

4. A spring that is stretched or compressed stores __________________ _____________.

5. When a force acts on a spring, is done. The work done is stored as elastic potential

energy.

6. Applications of elasticity

a) ______________is used to support our body when we sit on it them.

b) ______________enable passengers in a car to feel comfortable even when it travels on a bumpy road.

c) ______________is used to measure mass/weight which is stretched when a load is hung on it.

SECTION B : Factors that affect the elasticity of a spring. Complete the table below.The larger the smaller The shorter elasticity

Factor Relationship to elasticity

1. Length the spring, the larger the force constant of the spring.

2. Diameter of spring (coil) The larger the diameter of a spring (coil), the force constant

of the spring.

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3. Diameter of spring wire the diameter of spring wire, the larger the force constant

of the spring.

4. Type of material The of a spring depends on the material it is made of.

SECTION C : Answer all the question.

1. The force-extension graphs for two springs, R and S are shown below. Complete the table thatfollows.

5

Statement Spring R Spring S

The gradient of the graph ____N cm-1 ____N cm-1

The force constant of spring ____N cm-1 ____N cm-1

Force needed to extend 1 cm of the spring ______N. _______N.

The area under the graph when the spring is extented

by 5 cm

100_N cm

____N m

50 _N cm

____N m

E lastic potential energy when the spring is extented by

5 cm

___J ____J

From the graph, we may conclude that

Spring ___ is more stiff compared to spring____.When each spring is extented by 5 cm, spring _____stores more elastic potential energy than

spring ____

45

Extension, x (cm)

Force, F (N)

0

20

10

40

SR

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2. The figures below shows the arrangement of apparatus in an experiment to determine the relationshipbetween the extension, e of a spring T with weight, W. The relationship ofe and Wis shown in the graph.

a) Based on the graph,

i. Mark with a cross (x) the elastic limit of the spring.

ii. Name the law that is related to the graph before the elastic limit is exceeded.

iii. State the relationship between W and ebefore the elastic limit.

iv. Determine the value ofe when W= 8 N. Show on the graph, how you determine the value ofe.

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b) The spring stores energy when it is extended.i)Name the type of energy stored in the spring.

ii) Calculate the force constant of the spring in SI unit.

iii)Calculate the area under the graph, when the spring is extended from o cm to 4 cm.

iv) Calculate the energy stored in the spring when it is extended by 4 cm.

v) What is the relationship between area under the graph and the energy stores in the spring.

c) Another spring T is added parallel with the spring T as shown in the figure below.

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Sketch the graph of W against e for this experiment on the graph.

CHAPTER 3: FORCES AND PRESSURE

3.1 Understanding Pressure

Define pressure and state thatA

FP=

Describe applications of pressure

Solve problems involving pressure

1. What is meant by pressure?........................................................................................................................................

2. Choose ( ) the examples that apply the concept of pressure?

( ) Toothpaste ( ) Nail

( ) Larger and wider seat belt ( ) Knife

( ) Ship ( ) Aerofoil

3. A girl is going to take a walk on a soggy

field. There are two types of shoes as in

diagram 3.

Which type of shoes should she wear?

........................................................................................................................................

4. Diagram shows a cuboid of 2 kg on a table.

Calculate the pressure exerted on the table by the cuboid. Tick () the correct answer.

48

Spring T

Spring T

0.4 m

0.1 m


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Diagram

( ) 0.8 N m-2

( ) 50 N m-2

( ) 200 N m-2

( ) 500 N m-2

5. Diagram 5 shows different situations of a cuboid of 5 kg on a table.

Circle the diagram in which the cuboid exerts the least pressure on the table.

Diagram 5

3.2 Understanding Pressure in Liquids

relate depth to pressure in a liquid

relate density to pressure in a liquid

explain pressure in a liquid and state that P = h g

describe applications of pressure in liquids.

1. What is the relationship between depth of liquid and pressure?

.................................................................................................................................................................................

.

2. What is the relationship between density of liquid and pressure?

.................................................................................................................................................................................

.

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Diagram 3

3. Diagram 3 shows a container of oil.

Underline the correct answer

Point ( X , Y ) has the highest pressure?

4. The relationship of Pressure in liquid is, P =hg

What is represented by h, and g respectively?

h =.............................. = .............................

g =.............................

5. State one application of pressure in liquid.

.................................................................................................................................................................................

.

Diagram 6

Diagram 6 shows a glass full of alcohol.

What is the pressure at P? Tick () the correct answer.

[ Density of alcohol = 800 kg m-3 ]

( ) 1600 Pa( ) 16 000 Pa

( ) 160 000 Pa

( ) 1 600 000 Pa

3.3 Understanding Gas Pressure and Atmospheric Pressure

explain gas pressure

explain atmospheric pressure

describe applications of atmospheric pressure

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1. A student wrote several statements to explain the gas pressure.

However they were in the wrong order.

Rearrange the statements in sequence to explain the gas pressure.[Write numbers 1, 2, 3 or 4 in the sequence column]

Sequence Statements

Collisions of gas particles in the container occur very frequently.

The gas is made up of gas particles.

The collisions of gas particles on the wall of container give rise to gas pressure

The gas particles move randomly with high speed.

2.

Diagram 2

Diagram 2 shows a manometer connected to a gas tank.Determine the gas pressure shown.[ Atmospheric pressure = 76 cm Hg]

3.

Diagram 3

Diagram 3 shows a manometer.

What will happen to the mercury column Y if X is connected to a high pressure of gas tank?

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.............................

.

4. Underline the correct answer.

(a) The ( weight , mass ) of air on the earths surface caused the atmospheric pressure.

(b) A mountain terrain has a ( higher , lower ) atmospheric pressure than at the sea-side because the

air at the mountain terrain is ( thicker , thinner ).

5. It is found that a Fortin barometer reads 74 cm Hg at a highland whereas the reading is 76 cm Hg at the sea

side.Based on the statement, tick ()i. a correct inferenceii. a correct hypothesis

i ( ) The atmospheric pressure is influenced by the altitude( ) The atmospheric pressure is influenced by the type of barometer

ii. ( ) The higher the altitude from sea level the lower the atmospheric pressure

( ) The lower the altitude from sea level the lower the atmospheric pressure

6. Fortin barometer X reads 74 cm whereas Fortin barometer Y reads 76 cmHg.

Which of the following statements correctly explain the difference of atmospheric pressure in the terms of

altitude?Tick () at the correct statements.

The Fortin barometer X measured the atmospheric pressure at lower altitude.

The Fortin barometer X measured the atmospheric pressure at higher altitude.

The Fortin barometer Y measured the atmospheric pressure at lower altitude.

The Fortin barometer Y measured the atmospheric pressure at higher altitude.

8. List two applications of atmospheric pressure.

i . ...............................................................................................................................

ii. ...............................................................................................................................

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3.4 Appling Pascals Principle

state Pascals principle.Explain hydraulic system

Describe applications of Pascals principle.

Solve problems involving Pascals principle.

1. Pascals Principle states that

...............................................................................................

..............................

2. Some examples of the application of the Pascals Principle are

.. ,.......................

3. Diagram 3 shows a application of Pascals Principle.

State the relationship between F1, F2, A1 and A2.

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Diagram 3

.................................

4. The diagram 4 show one application where pressure is transmitted

equally through an oil. Name of the system : ..

Diagram 4

5. Diagram 5 shows toothpaste being squeezed out from the tube. The principle that explains the situation

below is

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Diagram 5

6. Diagram 6 shows a :..

Diagram 6

7. Diagram 7 shows a simple hydraulic system. A1 and A2 are cross

section area of the piston. A1 = 5 cm2 and A2 = 10 cm2.

Diagram 7

(a). What is the minimum force F1 which can lift a load of 100 kg ?

(b). What will happen to the hydraulic jack if the force F1 is less than the value found in 7(a)?

(c). Give one reason for your answer

............................

...................................................................................................................................................................

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3.5 Applying Archimedes Principle

Explain buoyant force

Relate buoyant force to the weight of the liquid displaced

State Archimedes principle.

Describe applications of Archimedes principle

Solve problems involving Archimedes principle

1. Buoyant force is the ..................................................................................................................................

.............................

2. Archimedes' Principle states that ..............................................................................................................

.........................................................................

.............................

3. The examples of application of Archimedes' Principle are:

.., ... , ..

4. What is the relationship between the buoyant force and the weight of water displaced ?

.......................................

5. Diagram 5 shows a spring balance supporting a metal block K in three situations.

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Diagram 5

(a) Compare the readings of the spring balance in Diagram 5A and Diagram 5B.

............................

(b) Name three forces that act on K when it is partially or totally immersed in water.

.., .,

(c) State and explain the relationship between the forces in (b).

............................

(d) Name the principle involved in question (c).

...........................

(e). (i). What will happen to the spring balance in diagram 5C if the water is

replaced with salt solution?

............................

(ii) Give one reason for your answer.

..............................

6. A submarine can sail on the sea surface and under the sea. Explain how a submarine on the

surface submerges.

a) The submarine has a ____________.

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b) Water is _________ in the ballast tank.

d) The submarine sinks into the water when its ___________ is more than the ____________ of the

water and its weight is equal/more than the _______.

7. A fisherman finds that his boat is at different levels in the sea and in the river, although the boat carries

the same load. Diagram A and B below illustrate the situations of the boat in the sea and in the river.

Diagram 7

Compare the levels of the boats in diagram 7 and the volumes of water displaced by the boat. Relating the

mass of the boat with its load, the volume of water displaced and the density of the water, deduce a relevant

physics concept.

a) The boat _________ more in the river than in the sea.

b) Sea water is ___________ than river water.

c) The _________ of the boat and its load is the same when it is in the

sea and in the river.

d) The boat floats because it is being balanced up by the _____________.

e) The upthrust is equal to the weight of _________________.

f) More water will be ___________ when the density is lower.

The boat _________ more when the density is lower.

8. Diagram A and B illustrate the working principle of a hydrometer. The depth to

which the test tube sinks depends on its surrounding liquid.

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Diagram 8

Explain how you would design a hydrometer that can determine a wide range of densities of liquid, using theidea of the working principle of hydrometer in diagram 8A and diagram 8B. Draw a diagram that shows thedesign of your hydrometer and in your explanation. Emphasized the following aspects:

- the stability of the hydrometer,

- the sensitivity of the hydrometer,

- the ability to measure a wide range of densities of liquids,

- the calibration of the hydrometer.

a) Draw a correct design of the hydrometer.

b) Put _________________ balls in the glass bulb, to ensure the hydrometer is upright.

c) Use a _________________ stem, to have a bigger interval of the scale.d) Use a suitable big bulb and a ___________ stem. So that the hydrometer does not sink fully in low

density liquid.

e) ______________ the hydrometer in a paraffin oil / alcohol. The scale and the level of liquid at the

stem will show the density of paraffin oil / alcohol. This is to make calibration for liquid of low

density.

f) ________________ the hydrometer into a carbon tetrachloride solution. This is the calibration for

liquid of high density. Make the scale at the stem using the upper and the lower level of density.

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3.6 Understanding Bernoulli's Principle

State Bernoullis principle

Explain that resultant force exists due to a difference in fluid pressure

Describe applications of Bernoullis principle

Solve problems involving Bernoullis principle

1. Bernoulli's Principle states that

..............................

2. The examples of application of the Bernoulli's Principle are:

i ..,ii ....,iii...,

iv.,v..

3. Diagram below shows a piece of paper hanging from a retort stand. When air flows from the nozzle ofan air pump, the paper changes its position as shown in Diagram B.

Diagram 3

(a) Compare the position of the paper in Diagram 3A and Diagram 3B.

.................................

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(b) F is a force that causes the paper to change its position. In box X, on Diagram B, indicate and label

the direction of F that acts on the paper.

(c) Explain how F is produced.

i............................

ii...........................

(d) (i) Compared to the position of the paper in Diagram B, how does the

position of paper change when the air flows faster ?.

.

(ii). Give a reason for your answer in (d)(i).

.

(e) Name the principle that causes the observation in Diagram B.

.

4. Diagram A below shows the situation of a sheet of paper before and when air is blown. Diagram B showsthe situation of canopy before the lorry moves and when the lorry moves at high speed.

Diagram 4

(a) Based on Diagram 4A and Diagram 4B :

(i) State two similarities for the situations in Diagram 4A and Diagram 4B.i.

ii

(ii) Compare the air pressure above and below the paper when air is blown.

(iii) Relate the speed of the air to the pressure of the air.

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(b) Name the principle involved in question (a)(iii).

5. Diagram 5 shows an instrument used to measure the speed of air.

Diagram 5

In Diagram 5A shown the level of coloured water in the U-tube is the same before air flows.

(a) Compare the speeds of air at P and at Q after air flows at diagram B.

(b) Mark the water level in the U-tube in Diagram B when air flows.

6. Diagram 6 shows a cross-section of a wing of a moving aero plane.

The wing of the aeroplane experiences a lift force.

Diagram 6

(a) Name the shape of the cross-section in Diagram 6.

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..

(b) Explain why the lift force acts on the wing of the aeroplane.

i

ii

iii

7. Diagram 7 shows a model of an aeroplane.

Diagram 7

You are required to give some suggestions to design a aero plane which can travel faster and morestable.

Using the knowledge on motion, forces and the properties of materials, explain the suggestion based on

the following aspects:- the surface of the plane

- the shape of the plane

- material used for the plane

- position of the wing

- the size of the wing

a) __________. To reduce air friction between air plane and air.

b) _____________ shape. To reduce air friction also.

c) ________________ material. To reduce the weight and easy to fly.

d) The wings are positioned higher up on the body so that the aeroplane is _________________ .

e) ___________. To increase the uplift (force)..

CHAPTER 4 : HEAT

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4.1 Understanding Thermal Equilibrium

Explain thermal equilibrium

Explain how a liquid-in-glass thermometer works

1. ( Heat , Temperature ) is the degree of hotness of a body.

2. ( Heat , Temperature ) is a form of energy.

3. A hot body has a temperature where as a cold body has a temperature.

4. The SI unit for heat is .

5. The SI unit for temperature is

6. Temperature is a *( base , derived ) quantity.

7. Heat is a *( base , derived ) quantity.

8. The figure shows two metal blocks in thermal contact.

(a) Energy is transferred from *( A , B ) to *( A , B ) at a faster rate.

(b) Energy is transferred from *( A , B ) to *( A , B ) at a slower rate.

(c) Temperature A will *( increase , decrease ).

(d) Temperature B will *( increase , decrease ).

(e) The net heat will flow from *( A , B ) to *( A , B ) until they are at the

same temperature.9. Two bodies are said to be in thermal equilibrium when :

(a) they are at the *( zero , same ) temperature.

(b) the net rate of heat flow between the two bodies is *( zero , same ).

10. Temperature is measured by a ..with works with the principle of ....

11. Name the physical property (thermometric property) which varies with temperature used in a liquid-

in-glass thermometer. ..

12. The liquids commonly used in liquid-in-glass thermometers are and .

13. Comparison of mercury and alcohol as a liquid-in-glass thermometer.

14. Complete the following table concerning a liquid-in-glass thermometer.

Features Explanation

64

Mercury Alcohol

Freezing point :

Boiling point :

Freezing point :

Boiling point :It (wet, does not wet) the tube. It (wet, does not wet) the tube.(Opaque , colourless)

Easy to read.

(Opaque , colourless)

It needs to be dyed.It is (poisonous, safe liquid). It is (poisonous, safe liquid).It is (cheap, expensive). It is (cheap, expensive).Conducts heat well, responds faster to temperature changes. Responds more slowly then mercury.

A

30C B80C


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The glass bulb is thin.

The bulb is made small.

The bore of the capillary tube is

narrow and uniform.

The walls of the long tube above the

bulb are made thick

15. Temperature of liquid, Cll

ll 0

0100

0100

=

,

Where, 0l = length of mercury at .. point.

100l = length of mercury at .. point.

l = length of mercury at point.

16. An uncalibrated thermometer is attached to a centimetre scale and reads5.0 cm in pure melting ice and 30.0 cm in steam. When the thermometer is immersed in the liquid y,the length of the mercury column is 15.0 cm. What is temperature of liquid y?

4.2 Understanding Specific Heat Capacity

Define specific heat capacity I

State that c= Q

m

Determine the specific heat capacity of a liquid

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Determine the specific heat capacity of a solid

Describe applications of specific heat capacity

Solve problems involving specific heat capacity

1. The of a substance is the quantity of heat

needed to increase the temperature of a mass of 1 kg by 10

C or 1 K.

2. Specific heat capacity, c =m

Q

Where, m =

Q =

= .

3. The unit of specific heat capacity is .

4. The quantity of heat absorbed or lost from a body is given by, Q =

5. How much heat energy is required to raise the temperature of 1.5 kg of water from 300

C to itsboiling point ? The specific heat capacity of water is 4200 J kg 1 0 C 1 .

6. Conversion of energy(a) Electrical energy from heater transformed into heat energy.

= m c

(b) Potential energy of a falling object transformed into heat energy.

= m c

(c) Kinetic energy of a moving object is transformed into heat energy when it is stopped due to

friction.

= m c

7. A 700 W electric heater is used to heat 2 kg of water for 10 minutes. Calculate the temperature rise ofthe water. The specific heat capacity of water is 4200 J kg 1 0 C 1 .

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8. A copper block weighing 2 kg is dropped from a height of 20 m. What is the rise in temperature ofthe copper block after it hits the floor. The specific heat capacity of copper is 400 J kg 1 0 C 1 .

9. A bullet traveling at 60 m s 1 hit a sand bag. The temperature of the bullet rises by 4.5 0 C.Calculate the specific heat capacity of the bullet.

10. 100 g of hot water at 90 0 C is mixed with 200 g of cold water at 30 0 C. Assuming that no heatis lost, calculate the final temperature of the mixture.

11. Complete the following table.Material has a high specific heat capacity Material has a low specific heat capacity

It takes a longer time to be heated.

It lose heat easily.

It is a heat insulator.

4.3 Understanding Specific Latent Heat

State that transfer of heat during a change of phase does not cause a change in temperature

Define specific latent heat (l)

State that l = Q

m

Determine the specific latent heat of fusion

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Determine the specific latent heat of 68vaporization

Solve problems involving specific latent heat

1. Matter exists in three states, that is solid, . and .. .

2. The heat released or absorbed at constant temperature during a change of state of matter is known as

.. .

3. Latent heat is released

Melting

condensation

4. Specific latent heat of.. is the quantity of heat that is needed to change 1 kg of a

substance from solid state to liquid state, without a change in temperature.

5. Specific latent heat of.. is the quantity of heat that is needed to change 1 kg of a

substance from liquid state to vapour state, without a change in temperature.

6. Specific latent heat, L =m

Q

Where, Q = latent heat absorbed or released by the substance

m = mass of the substance.

7. The SI unit for specific latent heat is . .

8. What is the quantity of heat required to melt 2 kg of ice at 0 0 C ? Specific latent heat of fusion of ice

= 336000 J kg 1 .

9. Temperature / 0 C

F

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Solid Gas


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90 D E

B C70

30 A

0 5 15 20 35 Time/minuteFigure shows the temperature- time graph for a substance, S of mass 2.0 kg, being heated using a500 W heater.

(a) Based on the graph state the physical condition of substance, S in

(i) AB : ..

(ii) BC : ..

(iii) CD : ..

(iv) DE : ..

(b)Melting point : .

(c) Boiling point :

(d) By using kinetic theory, explain why the temperature of substance, S in AB is increasing.

(e) By using kinetic theory, explain why the temperature of substance, S is constant in BC even thoughheat is still been supplied to it.

.................

..................................................................................................................................................................

(f) Calculate the specific heat capacity of the substance in solid state.

(g) Calculate the specific latent heat of vaporization of substance, S.

4.4 Understanding The Gas Laws

Explain gas pressure, temperature and volume in terms of the behavior of gas molecules

Determine the relationship between pressure and volume at constant temperature for a fixed mass of

gas ie Pv = constant

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Determine the relationship between volume and temperature at constant pressure for a fixed mass of

gas ie V/T = constant

Determine the relationship between pressure and temperature at constant volume for a fixed mass of

gas ie p/T = constant

Explain about zero

Explain the absolute/Kelvin scale of temperature

Solve problems involving the pressure, temperature and volume of a fixed mass of gas

1. Complete the table below about gas lawsBoyles Law Charles Law

PV

1 P T

Constant Variable :1. Mass of gas

2.


2. Pressure of gas


2.Boyles law states that the

pressure of a fixed mass of gas is

inversely proportional to its

volume at constant temperature.

Charles law states that Pressure law states that

P

0 V

V

0 T/ 0 C

P

0 T/ 0 C

P

0V

1

V

0 T/K

P

0 T/K

V

P

0 P

T

V

0 V

T

P

0 P

VP

0 V

TV

0 T

TP

0 T2. Figure(a) show 18 cm of air column trapped in a capillary tube by 4 cm of mercury. If the glass tube is inverted,

what is the length, L, of the air column trapped in the capillary tube? (Atmospheric pressure = 76 cm Hg)

4 cm L air

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18 cm air 4 cm

( a ) ( b )3. An air bubble released by a diver has a volume of 4.0 cm 3 at depth of 15 m. What is the volume of the

bubble at a depth of 10 m? (Atmospheric pressure = 10 m water)

4. The value -273 0 C is equivalent to K. This temperature is known as the 5. Convert 27 0 C to its equivalent temperature in Kelvin.

6. Convert 330 K to its equivalent temperature in degrees Celsius.

7. The volume of a gas is 5 cm 3 at 27 0 C. The gas is heated at fixed pressure until the column becomes 6

cm 3 . Calculate the final temperature of the gas.

8. A gas of volume 20 cm 3 at 47 0 C is heated until its temperature becomes 87 0 C at constant pressure.What is the final volume of the gas?

9. Before a journey from Parit Buntar to Ipoh, the air in a car tyre has a pressure of 200 kPa and atemperature of 27 0 C. After the journey, the air pressure in the tyre is 220 kPa. What is the temperatureof the air in the tyre after the journey?

10.The pressure of gas in a light bulb is 50.5 kPa at 30 0 C. Calculate the pressure of the gas when thetemperature inside the bulb rises to 87 0 C after the bulb is lighted up.

CHAPTER 5: LIGHT

5.1 Understanding Reflection of Light

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Describe the characteristic of the image formed by reflection of light

State the laws of reflection of light

Draw ray diagrams to show the position and characteristics of the image formed by a plane mirror,

convex mirror and concave mirror

Describe applications of reflection of light

Solve problems involving reflection of light

Construct a device based on the application of reflection of light

1. The characteristics of image when light from an object is reflected by a plane mirror includes

________________ , same size, _______________ from the mirror at perpendicular line and virtual.

2. The Law of reflection of light states that

i) the angle of incidence equals _________________

ii) the incident ray, the reflected ray and ______________________ are all lie at the same plane

3. (a) Complete the image of L in the diagram of reflection below.

(b) On the diagram above,

i. Show the light ray direction and the normal line of the mirror,

ii. show the angle of incidence and label as i, the angle of reflection and label as r

iii. show the distance of object, lo and distance of image l i perpendicular to the mirror

4. When the parallel rays are directed to concave mirror, the reflected rays will meet at a point

_______________ the mirror. It is called the __________________ of the concave mirror.

5. When the parallel rays are directed to convex mirror, the reflected rays will_____________. When therays are extrapolated, it will meet at a point ____________ the mirror, its the __________________.

6. Diagram below shows three parallel rays are directed to a concave and a convex lens, draw thereflected rays and indicate the focal point, F in each case. Show the direction of reflected rays.

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Mirror

Observers eye

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Relate the relation between centre of curvature, C, with focal point, F, of a mirror.

7. Convex mirror is often installed at the cornering of a hidden road and in the convenience store.

This mirror allows us to see ________ angle of objects but the size of the image is _________________.8. Diagram below shows a ray directed on a plane mirror.

i) Uses a red / blue ink ball pen, draw the normal line and the reflected ray for the given incidentray (use protractor and ruler to assist you).

ii) Now, using a pencil draw to show the mirror turned 10o clockwise. Thus, draw the newnormal line and new reflected ray. Observe the changes of angle for the reflected ray.

9. When a mirror turns xo, the angle between the two rays (incident and reflected) will have achange of__________________.

10. Mirror is used in measuring instruments like ammeter, voltmeter and galvanometer. It is to help

the user to read accurately and avoid _______________.

5.2 Understanding Refraction of Light

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Explain refraction of light

Define refractive index asrsin

isin =

5.2.3 Determine the refractive index of a glass or Perspex block

State the refractive index, ,

as Speed of light in a vacuum

Speed of light in a medium Describe phenomena due to refraction

Solve problems involving refraction of light

1. Light travels in a _______________ line, but when travels from one medium to another medium with

different ______________ , it changes direction. The change in direction when light ray travels from one

medium to another medium is called _____________________ .

2. The light ray that travels along the __________ line of the boundary between two medium does not bend.

3. When a light ray travels from an optically denser medium to a less dense medium, it refracts __________

far from the normal.

4. When a light ray travels from an optically less dense medium to a denser medium, the angle of incident

ray (at less dense medium) is______________ then the angle of refracted ray (at denser medium).

5. In the diagram below,a. draw two normal lines of the ray to and from the glass blockb. show the refracted light of the glass blockc. complete the direction of lightd. indicate the angle of incident, i , and the angle of refraction, r .

6. Angle of incident or angle of refraction is an angle made between the ray and the

_________________ .

normal line.

7. ______________________ says that the ratio ofr

i

sin

sinis a constant. It is known as the

_______________________of a medium (water / glass / perspex), n, where i > r .

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8. The speed of light ______________________ as it travel into a medium, therefore the refractive index of

a medium n = , simplified n =v

c.

9. Due to refraction of light,

a. a straight straw / rod appears ___________________ at the boundary of liquid.

b. the bottom of a pool liquid appears ______________________ to the surface that it actually is.

10. The refractive index of liquid can be calculated using, n = , simplified n =d

D.

11. In the diagram below use the following steps to construct the refraction of light of a coin in a beaker ofwater.a. draw the two normal lines at the boundary of liquid

b. draw and show the two rays refracted at the air (further from normal line)c. draw an eye at the correct positiond. from the eye, followed the refracted rays, extrapolated dotted lines backward and meet

above the original coin. Draw a dotted oval shape, to represents the image of the coin.

12. The phenomenon of refraction of light include ______________, sunrise, ____________, twinkling

stars at night and wriggling of distant objects on hot day.

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5.3 Understanding Total Internal Reflection of Light

Explain total internal reflection of light

Define critical angle (c)

Relate the critical angle to the refractive index i.ecsin

1=

Describe natural phenomenon involving total internal reflection

Describe applications of total internal reflection

Solve problems involving total internal reflection

1. Diagram below shows a light ray travels through a semicircle glass block. If the angle,of incident is small, most of the light is ______________ but some is ________________ .

Label in the diagram i) the refracted light and reflected lightii) the angle of incident, i and angle of refraction, r.

2. The critical angle, c is the incident angle, i when the maximum refraction occurs at r = ________

On the diagram below, label the critical angle, c and refraction angle, r.

3. The total internal reflection occurs when,

(a) i) light travels from a _________________ to a less ____________________ and

ii) when the incident angle, i is ______________________ the critical angle, c

(b) name the phenomena occurs in the diagram below. ____________________________

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4. Another formula of refractive index, n =csin

1

csin

90sino

=

5. The phenomenon of total refraction of lights includes

a) mirage in the desert

b) mirage on hot afternoon on highway

c) ___________________

6. The phenomenon of mirage occurs is due to the different layers of hot air, hot air on the ground is

_____________ dense compare with cold air at higher level on hot day. The water droplets from

the cloud are refracted ______________________ from the normal line. When the angle ofincident ray is ___________________ , it created a total internal reflection on the

___________________. Our eye sight sees ________________ as though there are water drops

on the ground.

7. Refers to the diagram given below:i) In each of the box fill in two of the following characteristics of air:

hot air, colder air, denser, less dense, ray (closer to / further) from normal lineii) Complete the ray diagram of mirage starts from the object.iii) Show how we can see the pool of water (mirage) on the highway.

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Object

Image Pool of water appears at the highway on a very hot day.

i.............

ii................

iii...............

...............

i.............

ii................

iii...............

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5.4 Understanding Lenses

Explain focal point and focal length

Determine the focal point and focal length of a convex lens and concave lens

Draw ray diagrams to show the positions and characteristics of the images formed by a convex

lens and concave lens.

Define magnification asu

vm=

Relate focal length (f) to the object distance (u) and image distance (v) i.e.v

1

u

1

f

1+=

Describe, with the aid of ray diagrams, the use of lenses in optical devices.

Construct an optical device that uses lenses.

Solve problems involving to lenses.

1. When light passes through a convex lens, the light _________________ to a point and we call it

_________________. Convex lens is also known as a converging lens.

2. Concave lens is also known as a ________________________ because light passes through it

diverge from a point, the focal point, F.

3. For the ray diagram below fill in the following labels:Principle axis, P, Optical centre, O, Focal point, F, focal length, f

4. Complete the following ray diagrams to find out the images of each one.Given the characteristics of images includes real or virtual, upright or inverted,diminished / smaller, same or magnified or larger. State the characteristics for each.

a)

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Characteristics

of image:

i...

ii.

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b)

c)

5. (a) When the object is too near from the convex lens, the image is virtual, magnified and upright.

(b) Concave lens produce only one type of image that is virtual, diminished and upright.

Base on the two statements above, draw the images for the following diagrams.

(i) (ii)

6. Complete the following ray diagram and name the characteristics for each.

7. The symbol for image distance is _______ and the symbol for object distance is ____.

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Characteristics

of image:i...

ii.

iii

Characteristics

of image:

i...

ii..iii.

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8. The formula for magnification m =dobjectofsize

Dimageofsize

,

,or m =

9. Given the formulavuf

111+= can be used to solve optical problems. Explain what does it means

when f is negative value, f is positive value, v is negative value and v is positive value.

f is negative : .

f is positive : .

v is negative :

v is positive : .

Physics Form 4 Module

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