CH 13 MOTION T5.pdf

1. THE MOTION OF VEHICLES ON LAND COMPARISON BETWEEN THE TWO STROKE AND THE FOUR STROKE ENGINE

FOUR STROKE ENGINE TWO SROKE ENGINE

In each cycle, the piston moves four strokes, two upward strokes and two downward strokes

In each cycle, the piston moves two strokes, one upward stroke and one downward stroke.

Power is released only on the third stroke, also called the power stroke

Power is released on every upward stroke

Combustion of fuel takes place only on the third stroke. During this stroke, an upward stroke, sparks (electrical) given off by the spark plugs ignite the air-fuel mixture

Combustion of fuel takes place on every upward stroke of the piston. Sparks (electrical) given off by the spark plugs ignite the air-fuel mixture.

Generally more efficient because the combustion process is more complete

Less efficient because the combustion process is incomplete.

The design is complex and bulky. The design is simple and less complex. COMPARISON BETWEEN PETROL AND DIESEL ENGINES

Petrol engine Fuel engine Diesel engine Spark plugs Means of fuel ignition Fuel injected into hot air Mixture of petrol and air Fuel in cylinder Hot air Quiet Noise level Noisy Less efficient Efficiency level About 40% more efficient More eco friendly Environment friendly Causes more pollution 2. THE COINCEPT OF SPEED, VELOCITY AND ECCELERATION Speed Velocity Acceleration What does it measure?

Measures how fast the distance is changing with time

Measures how fast the displacement (position ) is changing with time

Measures how fast the velocity is changing with time

Definition Rate of change of distance Rate of change of displacement Rate of change of velocity

Direction No specific direction Has specific direction Has specific direction Formula

Speed= Distance travelled Time taken

Velocity= Distance travelled Time taken

Acceleration= Change in velocity Time taken

SI Unit ms-1 ms-1 ms-2

CHAPTER 13 MOTION

3. THE CONCEPT OF INERTIA

All objects have inertia. Inertia is the natural property of the object to remain at rest if it is at rest or to continue in motion with the same speed in a straight line if it is already in motion.

Some effects of inertia: i) a sudden jerk may cause the strap of a bag to snap ii) passengers are flung forward when the bus stops suddenly iii) the head of a hammer can be tighten by knocking the handle on a hard surface.

SES 1511 Kelantan 2007 *The bolded and italic letter is the answer 247

Mass is the quantitative measure of inertia, also defined as the quality of matter of an object. It is measured in kilogram (kg). The bigger the mass, the higher the inertia.

4. THE CONCEPT OF MOMENTUM

Momentum is defined as the product of the mass and the velocity of the moving object. Its SI unit is kgms-1 If no external force act on a system, such as happen in a collision, the total momentum is

conserved and remained constant. This is the principle of conversion of momentum. The total momentum before and after the collision does not change.

5. PRESSURE

Pressure is force per unit area. Its unit of measure is Nm-2 or Pascal The two factors that affect the pressure acting on a surface area are:

P = F A

i) The contact area ii) The force acting on the surface area

6. THE PRINCIPLE OF HYDRAULIC SYSTEM IN EVERYDAY LIFE

Any increase in pressure in a fluid is transmitted equally in all directions. This is sometimes called Pascal principle or hydraulic principle as applied in hydraulic systems,

such as the hydraulic lifts, hydraulic pump and the hydraulic brakes.

F1F2

A2A1

At equilibrium state Pressure at piston 1 = Pressure at piston 2

A2

F2

A1

F1 =

7. THE MOTION OF VEHICLES IN WATER The common shape of vehicles is streamline shape. Archimedes’ principle can be conclude that: Upthrust = the apparent loss of weight of the object immersed in the fluid

= the weight of the fluid displaced The submarine has ballast tank and trim tanks to control its buoyancy.

o When the ballast tank is full, the submarine sinks. o When the ballast tank is empty, the submarine floats

8. THE MOTION OF VEHICLES IN THE AIR

The pressure of a fluid in motion changes. The relationship between the velocity of flow and pressure of the fluid is as stated in Bernoulli’s

principle. Bernoulli’s principle states that the pressure of a fluid decreases when its velocity (speed) is

increased. The wings of an aeroplane is said to be aerofoil. This causes the velocity of air flow above

the wings to be faster compared to that under the wings. This difference in velocity causes a higher pressure under the wings. The difference in pressure between the upper and the lower sides of the wings produces a lift. This lift directed upwards will push the plane to a higher altitude.


PAPER 1 1. Which of the following situation best described the concept of inertia? A. An ant falls to the ground faster compared to a monkey. B. A sharp knife cuts thru meat easier compared to a piece of wood C. A giant ship takes longer to come to a stop compared to a small boat D. A marble and a feather fall at the same rate if released in a vacuum cylinder. 2. Which of the following statement is correct for a vehicle moving at a constant speed of 100 km/hour? A. Having a deceleration. B. Not having any acceleration. C. Having a positive acceleration. D. Having a constant acceleration. 3. Which object has the greatest momentum? A. Object with a mass of 100 kg moving at a speed of 2 m/s B. Object with a mass of 2 kg moving at a speed of 100 m/s C. Object with a mass of 2 kg moving at a speed of 200 m/s D. Object with a mass of 200 kg moving at a speed of 0.5 m/s 4. The statement refers to one of the stroke in a 4-stroke engine

Piston moves downwards, both valves closed

What is the type of stroke? A. Intake stroke B. Power Stroke C. Exhaust stroke D. Compression stroke 5. The diagram shows four different strokes of a 4-stroke engine

i. ii. iii.

SES 1511 Kelantan 2007 *The bolded and italic letter

iv.

is the answer 249

Which of the following is the correct sequence of strokes? A. i, ii, iii, iv B. i, iv, ii, iii C. iii, ii, iv, i D. ii, iii, iv, i 6. The diagram shows power stroke of a 4-stroke engine.

What is the mistake? A. Piston should move downwards B. Only outlet valve should close C. Only inlet valve should open D. Both valves should open 7. The diagram shows one of the stroke in a 4-stroke engine.

What is the name of the stroke? A. Power stroke B. Intake stroke C. Exhaust stroke D. Compression stroke 8. Which of the statements below is true about an elephant standing still in the field? A. Its momentum is zero. B. It doesn’t have inertia. C. It experiences a constant acceleration. D. Its initial velocity is greater than final velocity.


9. Which of the ticker tape diagrams represents the motion of a vehicle approaching a red traffic light?

A B C D 10. Which of the shapes below produces the least drag?

A B C D

11. Which object will produce the most pressure on the floor if all the objects have equal mass? A C B D Floor 12. Which force will be produced by the jet engine of an aeroplane?

D

B A C


13. Which two properties will produce momentum? A. Mass and inertia B. Velocity and mass C. Acceleration and mass D. Acceleration and inertia 14. The diagram shows an aerofoil. Which of the following is the purpose of the shape? A. Lift B. Drag C. Thrust D. Weight 15. Which of the wooden blocks below experiences the greatest upthrust?

A B C D

Wooden block

16. When a fast stream of air is passed thru the funnel below , the ping pong ball stays in its place and doesn’t fall down.

Jet of air Which of the following statement explains the phenomena? A. Air pushes the ball to the wall of the funnel B. Gravitational force is not strong enough to pull the ball down C. Fast air flow produces area of low pressure above and around the ball D. Air flow will cause the ball to vibrate therefore preventing it from falling down


17. According to the principle of inertia, which object will swing the longest time?

200gram 500gram

1500gram 1000gram

B A C D 18. The diagram shows a metal bob is weighed in the air and immersed in water .

40N 35N

Weighed in the air Immersed in water How much water is displaced by the metal bob? A. 5 Newton B. 35 Newton C. 40 Newton D. 75 Newton 19. The diagram shows a hydraulic system .

50 Newton

W Small piston (cross sectional area= 1cm²)

Large piston (cross sectional area= 10cm²)


What is the force at W? A. 5 Newton B. 10 Newton C. 15 Newton D. 20 Newton 20. When we pull a roll of toilet tissue in a sudden pull, a portion of it will tear off. Which principle below is related to the occurrence? A. Bernoulli’s principle B. Principle of inertia. C. Archimedes principle D. Principle of momentum conservation 21. Below is the diagram of a simple hydraulic system.

M

L K

Load

W

A force is applied at W. Which statement is correct about what will happen? A. The pressure will be highest at point K B. The pressure will be highest at point L C. The pressure will be highest at point M D. The pressure at K, L, and M will be equal. 22. Bernoulli’s Principle says that if the velocity of a liquid in motion increases, its pressure decreases. In the diagram below, which area has the lowest pressure?

B

A

SES 1511 Kelantan 2007

DC

*The bolded and italic l
etter is the answer 254

23. The diagram shows two cylinders stacked on top of the other. A thin plastic card is placed between them.

Plastic card

Cylinders When the plastic card is pulled quickly, the two cylinders will remain in their places. What does this demonstrate? A. The principle of inertia B. The properties of plastic materials C. The principle of conservation of momentum D. The strength of gravitational pull on the cylinders 24. Which of the statements concerning a 4-stroke diesel engine is correct? A. It uses diesel, therefore less efficient B. It doesn’t use spark plugs for ignition C. It is cleaner compared to a petrol engine D. A mixture of air and fuel is injected into the combustion cylinder 25. A car move from rest and increase the velocity then move with uniform velocity . Which of the following line graphs represents their motions?

Time Time

Distance C

D

B Distance Distance A

Distance

Time Time


26. The diagram shows a piece of ticker tape containing five ticks.

4 cm . . . . . . What is the velocity of the object? A. 0.4 cm/s B. 4 cm/s C. 20 cm/s D. 40 cm/s 27. A bus with the mass of 20 000 kg is moving at a speed of 20 km/h. How fast must a motorcycle with a mass of 1000 kg go so that its momentum will equal that of the bus ? A. 50 km/h B. 400 km/h C. 500 km/h D. 2500 km/h 28. The picture shows an eagle is carrying a bleeding rabbit to its nest. Blood from the rabbit drips to the ground along the way at an interval of 3 seconds.

Blood drop

30 metres

How fast is the eagle flying to its nest? A. 0.33 metre / second B. 5 metres / second C. 10 metres / second D. 90 metres / second 29. We cannot easily immersed a ball in the water. Which of the following is the correct statement? A. The air in a ball under water is condensed. B. The air in a ball under water is much lighter. C. A ball under water experiences a great up thrust D. A ball under water experiences less gravitational force


30. Most of the injuries in an accident are caused by a sudden change of momentum. Which of the safety features shown below will help prolong the rate of change of momentum? A. Airbags B. Disc brakes C. Metal bumpers D. Crumple zone in the design of a car 31. A race car accelerates from rest to 20 m/s in 10s. What is the acceleration of the car? A. 0.5 m/s² B. 2 m/s² C. 10 m/s² D. 200 m/s² 32. Which of the following will happened to the inertia when the mass of an object increases? A. It is increases B. It is decreases C. It is becomes double D. It is remains unchanged 33. Which of the following is initiated the combustion in a 4-stroke diesel engine? A. Spark plugs B. Compressed air C. Mixture of air and petrol D. Diesel fuel sprayed into hot compressed air 34. The diagram shows water flows through a Bernoulli Tube.

Which of the following A,B,C and D has the lowest water pressure?

A DCB

Water 35. Jet engines cannot function in outer space. Which of the following statement is correct? A. Jet engines need air to burn fuel B. Jet fuel will not ignite in outer space C. Jet engines are not powerful enough to go that high D. Jet engines use liquid nitrogen which cannot be taken into space


PAPER 2

SECTION A

1. An experiment to obtain the velocity of a trolley moving down an inclined plane was

conducted. The set up of the experiment is shown in Diagram 1a. The ticker timer makes

50 ticks per second. A piece of the tape containing 10 ticks is shown in Diagram 1b.

Ticker timer

DIAGRAM 1a

DIAGRAM 1b

8 cm

a) Calculate the velocity of the trolley based on figure 1b.

………………………………………………………………………………………….. 40 cm/s

( 1 mark)

Trolley’s motion

DIAGRAM 1c


b) Tape in Diagram 1c shows dots when the inclination is greater. What can be said about the motion of the trolley?

………………………………………………………………………………………….. Trolley experiences acceleration

( 1 mark)

c) If a student wants to find out the effect of different inclination on velocity of the trolley,

what will be the:

i) Constant variable: …………………………………………………………….. Mass of the trolley

ii) Manipulated variable:………………………………………………………….. Degrees of inclination

iii) Responding variable: …………………………………………………………. Velocity of the trolley

(3 marks)

d) What is the operational definition of velocity in this case?

…………………………………………………………………………………………..

…………………………………………………………………………………………..

Velocity is the distance between two dots on ticker tape

( 1 mark)

2. A student is conducting an experiment to find out the relation between mass and the time

taken by a pendulum to make 10 complete swings. He uses 4 different weights. Table 1

shows the results he obtained.

Objects / Weight (g) Time for 10 swings

(s) A 100 10 B 200 20 C 300 30 D 400 40

TABLE 1

a) State the variables for this experiment:

i) Constant : ……………………………………………………….. Length of the string

ii) Maniplated : ……………………………………………………….. Weight of pendulum

iii) Responding : ……………………………………………………….. Time taken for ten swings


b) State a relation between mass and the time taken by the pendulum to make 10 swings

………………………………………………………………………………………….. The greater the mass, the longer the time of swing

( 1 mark)

c) From the table, plot a graph of mass versus time

Time (s)

400 100 200 300 0

50

40

30

20

10

500 Mass (g)

Figure 2 d) Based on your graph, estimate the time taken to make 10 swings if 500g weight is used.

……. ………………………………………………………………………………………….. 50 seconds

( 1 mark)

e) D is slower than A to make 10 swings, what concept is involved here ?

……. …………………………………………………………………………………………..

Concept of inertia

.


3. A student carried out an experiment to find a relation between mass and momentum. The set up is shown in Diagram 2. Results are presented in Table 2.

Sand area

Inclined plane

DIAGRAM 2

Number of trolley in stack Distance travelled in sand area (cm) 1 10 2 15 3 20

TABLE 2

a) Write a hypothesis for the experiment.

…….………………………………………………………………………………………….. The more trolley in a stack, the longer the distance in sand area they will travel ( 1 mark)

b) State the variables for this experiment:

constant : ……………………………………………………………………….. The inclination of the plane

manipulated : ……………………………………………………………………….. Number of trolleys in stack

responding : ……………………………………………………………………….. Distance travelled in sand area (3 marks)

c) Besides mass, state another factor which influences the momentum …….…………………………………………………………………………………………..

velocity

( 1 mark) e) What is the operational definition for momentum in this experiment?

…….………………………………………………………………………………………….. Momentum is the distance of trolley travelled in sand area.

( 1 mark)


SECTION B 1. Diagram 3 shows a piece of ticker tape containing dots made by a moving trolley. The ticker timer makes 50 ticks per second.

DIAGRAM 3Trolley’s movement

2 cm 1 cm

a) What is the initial velocity of the trolley?

…….………………………………………………………………………………………….. 50 cm / second ( 1 mark)

b) From the ticker tape, calculate the acceleration of the trolley

…….…………………………………………………………………………………………..

75 cm/sec - 50 cm /sec 0.1 s = 250 cm/s²

( 1 mark)

c) What is the acceleration of a vehicle moving at a constant speed of 100 km/h?

…….………………………………………………………………………………………….. Zero (no acceleration) ( 1 mark)

d) How far will a car have travelled if it moves at a speed of 50 m/s for two minutes? …….………………………………………………………………………………………….. 6000 metres // 6 km

( 1 mark)


2. Diagram 4 shows pieces of ticker tapes containing ten ticks put side by side.

Time Time 10 cm

3 cm

Velocity

Time (iii)

Velocity

(ii)

Velocity

(i)

DIAGRAM 4

a) Which diagram represents an acceleration?

…….………………………………………………………………………………………….. Diagram ii

( 1 mark)

b) What can be said about the acceleration of the object in diagram (i)?

…….…………………………………………………………………………………………..

50cm/s - 10cm/s 0.08s = 500cm/s²

( 1 mark)

c) Calculate the acceleration of the object in diagram (ii)

…….………………………………………………………………………………………….. The object does not experience any acceleration

( 1 mark)

d) State the term used to explain the motion of the object in diagram (iii)

…….………………………………………………………………………………………….. Deceleration

( 1 mark)


3. Table 3 shows a summary of a 4-stroke engine operation.

Induc

Comp

Powe

Exhau

a) Cob) Sta

…Pe

…

d)

… …

e)

…

SES 1511 K

Stroke Intake

valve

Exhaust

valve

Piston

movement

tion Open Close Down

ression Close Up

r close

Close

Down

st

Close

Open Up Close

TABLE 3

mplete the table te one difference between a 4-stroke petrol engine and a 4-stroke diesel engine.

….………………………………………………………………………………………….. trol engines use spark plugs for ignition but diesel engines don’t

….…………………………………………………………………………………………..

( 1 mark)

A lorry with a diesel engine cannot be started. The driver says it is caused by bad spark plugs. Do you think the driver is right ? Give your reason.

….…………………………………………………………………………………………..

….…………………………………………………………………………………………..

No, because diesel engines don’t use spark plugs

( 1 mark)

Give one example of vehicle used 2-stroke engine.

….………………………………………………………………………………………….. Lawn mower engine ( 1 mark)

elantan 2007 *The bolded and italic letter is the answer 264

4. Diagram 5 shows a Bernoulli Tube with water flowing thru it. a) Mark the water level in column X, Y and Z ( 1 mark)

b) Arrange points K, L, and M beginning with the highest pressure to the lowest Highest : …….……………………………………………………… Moderate : …….……………………………………………………… Lowest : …….………………………………………………………

( 3 marks)

c) Without column Y, water is still flowing from K to M. Explain the situation in term of pressure at K and M ……………………………………………………………………………………………………..

( 1 mark)

d) The Bernoulli Tube is turned upside down as in figure 4 below, air is blown thru it. Mark the

water level in column S, T, U

X Y Z

K L

M

Water flow

DIAGR AM 5

water

S T U

Air flow

Point K

Point M

Point L

Pressure at K is higher compared to M

DIAGRAM 6


SECTION C

Same amount of force can produce different amount of pressure depending on the area of contact surface.

1.

a) Write a hypothesis for this experiment (1m) You are given 2000g weight, a bed of plasticine , three different wooden blocks with different surface areas (1 cm ², 4 cm², 25 cm²) plan an experiment to prove the statement, your report must include the followings:

i) Aim of the experiment (1m) ii) Variables (2m) iii) Procedures and methods (4m) iv) Tabulation of data (2m)

ANSWER Hypothesis:

The smaller the surface contact, the bigger the resulting pressure Aim of the experiment : To find a relation between pressure exerted and surface contact area Variables: Constant : weight Manipulated : surface area of wooden blocks Responding : resulting pressure // Depth in plasticein bed Procedures and methods

Wooden block with 25 cm² is set standing on the plasticein bed. 2000g weight is then let to press down on it. The depth of wooden block is pushed into the plasticein is measured. Steps 1 to 3 is repeated using blocks with 4 cm² and 1cm². Results are recorded in a table

Tabulation of data

Wooden block

Surface contact (cm²)

Depth in plasticein bed (cm)

1 25 2 4 3 1


2. a) A fisherman finds it very difficult to maneuver his fishing boat out from where he tied it, he then decided to use his much smaller sampan instead. Elaborate and the fisherman’s efforts in maneuvering his fishing boat and his sampan in term of inertia.

(4m)

b) Diagram 1a and 1b shows two phenomena which occur when a cargo lorry hits a concrete block and a trolley with wooden block on it hit the barrier

Concrete block

Wooden block

Barrier

Diagram 7a

Study both diagrams and then develop the concept of inertia

Your answer should cover the following aspects:

i) Two common characteristics of inertia ii) Initial concept of inertia iii) Give another example of phenomenon involving inertia iv) Give an example which is not involve of inertia v) Develop the actual concept of inertia

ANSWER a)

A fishing boat is much bigger and has more inertia comsampan.

The fishing boat is much more difficult to move and onhard to stop its movement, therefore makes it more diff

Sampan is much smaller and has less inertia. This makto move or stopped, therefore it is much easier to mane

SES 1511 Kelantan 2007 *The bolded and italic letter is the answe

Diagram 7b

.

(2m) (1m)

(1m) (1m) (1m)

pared to smaller

ce it has moved it is icult to maneuver. es the sampan easier uver.

r 267

b) Two common characteristics of inertia

Both objects are moving Both object have tendency to continue move in the same direction Both are resist to stop immediately

Initial concept of inertia

The characteristics of the moving objects to continue moving in the same direction is an inertia

Example and non -example

Example :A magician pulling a table cloth without felling the dishes Non example : A tennis ball stopped and rebounded on the surface of a racket

Actual concept

Inertia is the characteristics of the moving objects to continue moving in the same direction and resist to stop immediately

3. a) ) Momentum is a product of velocity and the mass of the moving object. Using this

statement, elaborate on the inertia and momentum of a sleeping elephant and a speeding bullet.

(4m)

b) A car manufacturer has just released its latest model. It received a lot of complaints from buyers about the lack of safety measures on the car. State methods that can be used by the manufacturer to help solve its problem.

Your argument / answer should include the followings:

i) Identifying the problem (1m) ii) Clarification of the problem (1m)

iii) Methods to solve the problems (3m) iv) The best method chosen and the reason for it (1m)

ANSWER a)

Momentum is the product mass and velocity. An elephant has a great mass and it has a very great inertia but when it is

sleeping, its velocity is zero therefore its momentum is zero. A bullet has only very small mass therefore its inertia is also small, but

when it moves with such a great velocity, it possesses a very great momentum that can kill its targets.


b)

Identifying the problem : Lack of safety features Clarification of the problem : Cars are too dangerous, buyers want more safety Methods to solve the problems 1. to add air bags - most injuries come from the front 2. to add more crumple zones - to prolong the time of impact 3. to add more reliable braking system - stopping more safely 4. to add side safety bars - guard against impact from the sides features added to the cars. The best method chosen and the reason for it: Air bags – because most injuries come from the front. Collisions usually occur head on.


CH 13 MOTION T5.pdf

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