Introduction to Physics

Chapter 1

Introduction to Physics

PHYSICSFORM 4

Cikgu Desikan

FO

RM

4 P

HY

SIC

S

2015

1. Understanding Physics

2. Understanding base quantities and derived quantities

3. Understanding scalar and vector Quantities

4. Understanding measurements

5. Analysing scientific investigations

2007 2008 2009 2010 2011 2012 2013 2014

P1 3 3 3 2 3 3 4 1

P2

A - - - 1 - 1 - -

B - - - - - - - -

C - - - - - - - -

P3A - 1 1 1 - - 1 -

B - - - - - - - -

Analysis of Past Year Questions

Learning Objectives :

Dear students,

With the new day comes new strength and new

thoughts.

Introduction to Physics

Chapter 1

Cikgu Desikan

Concept Map

Dear students,

By failing to prepare, you are preparing to fail !!!

Introduction to Physics

Physics

ConceptsPhysics Quantity Measurement Scientific

Investigation

Field of

Physics

Base

Quantity

Approximation

Introduction to Physics

Derived

Quantity

Base Unit Derived Unit

Prefix Scientific

Notation

Conversion of

Units

Instrument for

Measurement

Error

Accuracy

Sensitivity Consistency

Chapter 1

1.1 Understanding Physics

Study of ___________________ phenomena and the properties of ____________________ .

What is Physics?

Fields of study

in physics

1.__________ & ________

Investigate the action of

force and motion

2. _________________

Studies the influence of

heat on different

types of matter 3. ________________

Explains the different

phenomena due to light

4. _________________

Understand the

properties of different

types of waves and

their uses

6. ___________

Studies the use of

electronic devices in

various fields

5. _______________

Investigates the

interactions of electric &

magnetic fields

7. ______________

Study of nuclear

structure and their

application

4

Derived quantities

(symbol)Expressed in base quantities Derived units

Area, A

Volume, V

1.2 Physical Quantities

Physical Quantities is a physical

characteristic that can be measured.

All physical quantities can be classified

into two groups :

1. ____________________________

2. ____________________________

Base quantities

Base quantities are quantities that cannot be

___________ in terms of other base quantities.

Base quantity Symbol S.I. Unit

Symbol

for S.I.

Unit

Derived quantity is one which obtained by

__________________ base quantities by

multiplication, division or both these

operations. Its unit is derived from a

similar combination of the base units.

1

2

5

Derived quantities

6Derived

quantities

(symbol)

Expressed in base quantities Derived units

Density ,

Velocity , v

Acceleration, a

Momentum, p

Force, F

Pressure, P

Weight, W

Scientific form

Write the following quantities in standard

form :

The values of measurements which is either

very large of very small are written in

Standard Form so as to be neater, brief and

easier to read.

A x 10n , 1 < A < 10 and n = integer

Prefix ValueStandard

formSymbol

Tera1,000,000,000,

000

Giga 1,000,000,000

Mega 1,000,000

Kilo 1,000

Hecto 100

Deca 10

Deci 0.1

Centi 0.01

Mili 0.001

Micro 0.000 001

Nano 0.000 000 001

Pico0.000 000 000

001

Prefix is used to simplify the expression of very

big or very small numerical values of physical

quantities

7

a. Radius of the earth = 6 370 000 m

b. Mass of an electron

= 0.000 000 000 000 000 911 kg

c. Size of a particle = 0.000 03 m

d. Diameter of an atom = 0.000 000 072 m

e. Wavelength of light = 0.000 000 55 m

Prefixes

Convert each of the following measurements

into metre, m

(a) 2.98 Tm

(b) 298 km

(c) 2.98 m(d) 2.98 x 10-1 Gm

(e) 2.98 x 10-3 Mm

(f) 29.8 x 107 nm

(g) 298 x 104 m

8

Conversion of Units

Exercise 3.1

9Convert

a. 4 m2 into the units of cm2

b. 30 cm2 into the units of m2

c. 2.5 m2 to unit of mm2

d. 500 mm2 into the units of m2

e. 200 m3 into the units of mm3

f. 11.5 cm3 into the units of m3

g. 72 km h-1 into the units of ms-1

h. 5 g cm-3 into the units of kg m-3

1.3 Understanding Scalar and Vector Quantities

Distance(s) Displacement(s)

Total of the path traveled Distance between measured

along a specific

quantity quantity

Speed Velocity

Rate of of distance Rate of change of displacement

Speed = Velocity =

quantity quantity

10

Scalar Quantities Vector Quantities

Distance

Velocity

Work

Area Force

Examples

Consistency in measurements

refers to how little deviation

there is among the

measurements made when a

quantity is measured several

times.

Accuracy of a measurement

is how close the

measurement made is to the

________

_________of the quantity.

Sensitivity of an instrument is

its ability to detect a

______________ in the

quantity to be measured in a

short period of time.

Consistency Accuracy Sensitivity

Shooter Consistency Accuracy

A

B

C

D

The diagram shows the result for four shooters A, B, C and D

in a tournament. Every shooter shot five times.

(Use High / Low)

11

1.4 Measuring Instruments

ERROR

Error is ________________caused by measuring instrument or the_____________ or the

____________________ of the surroundings.

Systematic Error Random Error

Caused by:i. Condition of the measuring instrument

ii. Condition of environment

Caused by:i. Surroundings factors, such as

temperature and wind

ii. Carelessness of the observer

Examplei. ______________________________

ii. Inaccurate calibration

Examplei. Parallax error ii. Error in counting

iii. Natural errors (sudden change)

Way of correctioni. Proper calibration

ii. Adjust the instrument frequently

Ways of correctioni. Take several readings and calculate

the average value.

A parallax error is an error in reading an instrument because the observers eyes and pointer are not in line / perpendicular to the plane of the scale.

1. position of eyes must be in line/ perpendicular / 90o with the scale of the reading to be taken.

2. When taking reading from an ammeter, we must make sure that the eyes are exactly in front of

the pointer, so that the reflection of the pointer in the mirror is right behind 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 parallax error.

How to avoid parallax error?

12

Parallax Error

Measuring Instruments & Accuracy

Physical Quantity Measuring Instrument

Length

Current

Mass

Temperature

Time

Voltage

AB

C

Pointers image can be seen Pointers image is behind the pointer

13Parallax Error

13

The tail is used to

measure depths

2

Vernier calliper reading = _________

No Zero error

VERNIER CALLIPER

Function Measurement

14

10

0 5 10

Negative zero error

15

Main Scale

Vernier Scale

Positive zero error

Sixth mark on the Vernier scale is in line with

a mark on the main scale

Positive zero error

=

10

0 5 10

Main Scale

Vernier Scale

Sixth mark on the Vernier scale is in line with

a mark on the main scale

Negative zero error

=

1. Write down the readings shown by the following:

0 1

0 105

b)0 1

0 105

a)

Try this!!!

Reading of the main scale

=

Reading of the thimble scale

=

Diameter of ball bearing

=

16

MICROMETER SCREW GAUGE

The object which to be

measured is placed

between the jaws (spindle).

The thimble is

turned until its jaw

touches the object.

The ratchet knob

prevents

overtightening by

making a click

sound when the

micrometer is ready

to be read.

main scale

thimble scaleHorizontal

reference

line

00

5

40

45

0

05

40

10

45

No Zero Error

CW

ACW

17

To elliminate the zero error ***

Correct Reading = Reading Obtained Zero Error

Horizontal

reference

line

0 mark

0

05

10

45

Horizontal

reference

line

2nd mark

above 0

Horizontal

reference

line

3th mark

below 0

1. Write down the readings shown by the following:

0 105

2 3c)

0 105

3 4a)

0 105

1 2d)

0 105

6 7b)

Exercise 3.4

2. Write down the readings shown by the following micrometer screw gauges.

a) b)

18

19

3. The following diagram shows the scale of a vernier callipers when the jaws are closed.

The following diagram shows the scale of the same vernier callipers when there are 50

pieces of cardboard between the jaws. Determine the thickness of one piece of cardboard.

0 1

0 105

5 6

0 105

(a) (b)

Sensitivity & Accuracy of Measuring Instruments

Instrument Sensitivity Accuracy

Metre Rule

Vernier Calliper

Micrometer Screw Gauge

Ammeter

Miliammeter

Thermometer

Mechanical stopwatch

Digital stopwatch

Miliammeter Thermometer Mechanical Stopwatch

20

1.5 Scientific Investigation

The problem is identified and stated by

asking question. The problem is usually

arised from an observation

The question asked must be one that can

be solved experimentally.

_______________________________

The quantity whose values we deliberately

choose to change or a primary variable

which causes other secondary variable to

change.

________________________________

The quantity whose value depend on the

manipulated variable or a secondary

variable which changes in response to the

change in the manipulated variable.

________________________________

The quantity whose value is kept constant

throughout the experiment.

2

1

21

AnalysisProcedure

Apparatus

Identify the problems/

questions / situations

Inference

Identify the

variables involve

Hypothesis List out

Aim

Tabulate

Design and

carry out

experiments

.Scientific Investigation.

A general statement about the relationship between

a manipulated variable and a responding variable.

The hypothesis should be written as :

The greater the, the greater the.Or

The bigger the, the smaller the..

Aim

A statement to show the investigation of the

variables involve. The aim of the experiment should

be written as:

To investigate the relationship between ..and Apparatus

List the apparatus and materials used so that at

least a set of data for manipulated and responding

variables can be determined. State the arrangement

of the apparatus that can function by drawing a

labeling diagram .

Procedure

1. State the method of controlling the manipulated

variables

2. State the method of measuring the responding

variables

3. Repeat the experiments at least four times.

When the data is organised in a table, it is

easier to analyse than recorded randomly.

Plot a graph of ( Responding variable) against

(Manipulated variable)

How to analyze the data ?

(a) Determine the relationship between two

variables.

(b) Determine the gradient of the graph

Based on the analysis and data interpretation,

make a rational conclusion

Report must be written after the scientific

investigation is completed.

The report must consist of aim, problem

statement, hypothesis, variables, apparatus and

material, procedure, result, discussion and

conclusion.

3

4

5

6

7

8

22

xy

0x

y

0

y decreasing linearly with

x

F

a

a F

m

a

1

m

a

0 0 0

a 1m

a 1m

a is inversely

proportional to ma is directly proportional to

1

m

Relationship between two variables

23

2. Which of the following is the best graph ?

The equation of the graph above is

A) P = 10Q + 5 B) P = 2Q + 10

C) P = 2Q + 10 D) P = 5Q 10

1. Which of the following force-compression

graphs shows that the compression,x of a

spring is directly proportional with the force

that is applied, F?

3.A. B.

x

F

x

F

x

F

x

F

24

C. D.

A. B.

x x

F F

C. D.

x x

F F

Q

P

5

10

Revision Questions

25

4. Table shows the readings of the length of a rod as recorded by two students, X and Y

Reading of student X/cm Reading of student Y/cm

2.42 2.43

2.38 2.41

2.40 2.38

2.36 2.34

a) What was the instrument used by both students?

b) Why four readings were taken for each measurement?

c) What is the average value of the readings made by

i) student X ?

ii) student Y ?

d) Which set of reading is more accurate? Why?

e) Apart from the instrument in (a), what instruments can be used although they are

less accurate?

Load

W/N

Time for 10

oscillations, t/s

Period of

oscillation, T/sT2/s2 W/T2 N s-2

1.0 6.7

2.0 9.5

3.0 11.6

4.0 13.4

The above table shows the experimental data that is obtained by a student using the

weighted spring oscillation system.

a) Name the variable that is manipulated.

b) Name the variable that responds.

c) Complete the above table with the corresponding values.

d) State the derived unit for W/T2.

e) Draw the graph of T2 against W.

f) Interpret the shape of the graph that you have drawn.

g) Calculate the gradient of your graph.

h) Write one relationship between the load and the period.

5.

26

10

0.2

27

DO YOU WANT TO GET

THINK..AND ACT NOW !!!

But HOW ?

HOW TO SCORE A+ PHYSICS ?

1. MASTER THE DEFINITION FOR PHYSICS TERMINOLOGY

2. MASTER THE PHYSICS PRINCIPLE AND THEIR APPLICATION

3. MASTER THE PHYSICS LAW & APPLICATION

4. MASTER THE PHYSICS RULE

5. MASTER THE PHYSICS FORMULA

6. KNOWING THE PHYSICS EXAMINATION FORMAT

7. MASTER THE METHOD OF ANSWERING QUESTION

8. MASTER THE METHOD OF ANSWERING

9. MASTER ALL THE PHYSICS EXPERIMENT

10.MASTER THE PHYSICS CONTENT USING

11.ANSWER THE PAST YEARS SPM EXAM PAPERS (Min 5 yrs)

12.MASTER THE DRAWING SKILL

13.MASTER THE WORKING PRINCIPLE OF INSTRUMENT

14.MASTER THE GRAPH SKILL

15.MASTER THE UNIT CONVERSION SKILL

16.MASTER CALCULATION SKILL

17.MASTER THE QUESTIONS SKILL ANALYSIS