Physics ATP Notes

 Q1. How to check for zero error in a:

(i) Vernier caliper

(ii) Micrometer screw gauge

(iii) Meter rule

(iv) Stopwatch

Ans:

(i) Close the jaws of the vernier caliper fully. When the zeros of both MAIN SCALE and

VERNIER SCALE are not aligned together, the zero error is present.

(ii) Before placing an object, turn the thimble until the spindle and anvil meet. If the

reading on the thimble is not alligned with the zero mark on the datum line, a zero error

is present.

(iii) Refer to this.

(iv) Just check what the stopwatch reads on reset. If it isn't 00:00, a zero-error is

present. Readings are subtracted accordingly.

Q2/3. How to check for zero error in a:

(i) Voltmeter

(ii Ammeter?

Ans: For both of them, disconnect them (from the circuit) and check if the pointer is

pointing at the zero mark on the scale. If they aren't, a zero-error is present.

Q4/5. Why the pointer reading ammeter/voltmeter is gently tapped before taking a

reading?

Ans: To reduce the friction between the needle and the pivot.

Q6. When making a ray diagram, why should rays and normal be as thin as possible?

Ans: Thin lines make it possible to obtain precise readings; with thick lines it is difficult

to measure accurate angles (of incidence, reflection etc.).

Q7. What is the purpose of a rachet in a micrometer?

Ans: To prevent undue pressure from being exerted.

Q8. A liquid reaching the maximum temperature quickly. Give one reason.

Ans: It is due to convectional currents. The water expands and gains heat energy and

its density lowers down, and it moves upwards and the lower part of the apparatus is

replaced by cold water which has higher density.

Q9. Why is the temperature 20°C marked on the measuring cylinder?

Ans: The scale on the cylinder is calibrated to give accurate readings when the liquid is

at 20°C.

Q10. Why an image is measured from a position behind the screen rather than front?

Ans: If it was measured from the front, it would block the rays of light and disturb the

apparatus.

Q11: WHAT IS A MEANT “GOOD ELECTRICAL” CONNECTION?

Ans: It means that the components are connected properly and are tightly screwed in

the circuit. This also reduces the circuit's internal resistance.

Q14: STATE ONE PRECAUTION, OTHER THAN AVOIDING PARALLAX ERROR

THAT SHOULD TAKE WHEN USING A SCHOOL LAB THERMOMETER, TO ENSURE

ACCURATE MEASUREMENT OF TEMPERATURE?

Ans: Check the mercury level when the reading becomes steady. If the thermometer is

in a liquid, make sure it is 1/3rd immersed and that the liquid is stirred before taking the

reading.

Q16: WHAT IS THE AFFECT OF “LENGTH” OR “MASS” ON TIME PERIOD OF

PENDULUM?

Ans: Length - The period of a pendulum increases with length.

Mass - No effect.

Q17: WHAT ARE THE CONDITIONS TO GET ACCURATE FIXED POINTS?

Ans: Immerse 1/3rd of the thermometer into the funnel containing ice, avoid parallax

error when reading the temperature on the thermometer, use ice shavings to ensure

good contact between the bulb of the thermometer and the ice, wait for the temperature

to become steady before taking the reading, etc. Ice point is 0°C and steam point is

100°C.

Q18: WHY WHILE DETERMINING THE BOILING POINT OF WATER,

THERMOMETER IS HELD IN STEAM?

Ans: Because the steam is pure and has specific melting point. If the reading is taken

from the water, it may not accurate as water may not be pure.

Q20: WHAT OBSERVATION MADE DURING THE EXPERIMENT WOULD CONFIRM

THAT THE GIVEN METAL IS A GOOD CONDUCTOR OF HEAT?

Ans: Experiment - Using 4 rods (copper, iron, glass and wood) which have the same

dimensions, coat one end of the rods evenly with wax. Then fill a tray of water in boiling

water and submerge the end of the rods in the tray. From observation, the wax melts

the farthest along the copper rod, showing that copper (a metal) is a good conductor of

heat while the other rods (insulators) are poor conductors of heat.

Q22: WHAT IS THE PUPOSE OF LAGGING?

Ans: Lagging is done to provide heat insulation (in boilers, pipes etc.) and trap heat from

escaping.

Q23: HOW YOU MIGHT CHECK THAT YOU HAVE MADE GOOD ELECTRICAL

CONNECTIONS?

Ans: Ensure that all components are screwed in tightly and that they work properly. If

the resistance of the circuit is low, the electrical connection is usually good.

Q24: GIVE A REASON FOR MAKING THE LENGTH OF EACH NORMAL AT LEAST

6CM?

Ans: This will help in measuring angles accurately as the radius of a protractor is

normally 6cm.

Q25: WHAT ADVANTAGE IS THERE IN USING TRACING PAPER FOR THE

SCREEN?

Ans: The image of the object can be viewed without obstruction of light. Also, the size of

the image can be conveniently measured by using a metre rule on the back of the

tracing paper without disturbing the apparatus.

Q26: WHY THE EYE NOT PLACED TOO CLOSE TO THE END OF THE RULE?

Ans: If the object is too close, the distance between the object and retina is low and

hence the image of the object is not formed on the retina, so we cannot see the object

clearly.

Q27: WHAT WOULD BE THE EFFECT ON THE IMAGE IF THE CENTRE OF THE

OBJECT AND THE CENTRE OF THE LENS ARE NOT AT THE SAME HEIGHT?

Ans: If they aren't parallel to each other, the image will be partial or blurred.

Q28: WHAT IS THE PURPOSE OF VARIABLE RESISTOR?

Ans: To adjust the current in the circuit.

Q30: BEFORE CLOSING THE SWITCH, WHY IS THE RHEOSTAT ADJUSTED TO

ITS MAXIMUM VALUE?

Ans: This makes sure minimum current flows in the circuit, so when the circuit is closed

the ammeter doesn't get damaged.

Q31: WHY IS A COMPASS TAPPED WHEN BEING USED?

Ans: To eliminate friction on the compass needle.

Q32: WHAT IS THE ADVANTAGE OF USING SMALLER COMPASS?

Ans: It is can be used to allign the weak magnetic fields.

Q33: WHY SHOULD CARD MOVE FREELY ON THE PIVOT? (referring to a card being

hung from a hole on a support)

Ans: To ensure the card does not stick to the pivot due to friction (which ensures that

the card is hanging in equilibrium position).

Q34: WHAT IS PLUMBLINE?

Ans: A line from which a weight is suspended to determine the depth or verticality.

Q35: WHY THE PLUMBLINE SHOULD HANG SO THAT IT ALMOST TOUCHES THE

CARD?

Ans: This will help in avoiding parallax error.

Q37: WHAT IS THE MEANING OF OF C WRITTEN ON A THERMOMETER?

Ans: It means the temperature is measured in Celcicus.

Q38: WHAT PRECAUTIONS ARE TO BE TAKEN WHILE MAKING A CIRCUIT?

Ans: Ensure that all connections are tight, make sure the components are functional

and clean, use a DC supply with low voltage (to minimize potential hazards), make sure

the power supply has a rating nearly equal to the lamp or bulb, make sure ammeter is in

series and voltmeter is in parallel, etc.

Q39: WHAT IS A JOCKEY?

Ans: A jockey is a metal slider that wears away a line of the insulation so it can make

electrical contact with the metal underneath.

Q40: HOW WOULD YOU CLEAN THE DIRTY JOCKY?

Ans: Rub the jockey with sand paper.

Q41: HOW COULD LID HELPS TO KEEP THE CONTENTS OF LAGGED

CONTAINER FROZEN?

Ans: It prevents heat from the surroundings entering the container.

Q42: WHY THERMOMETER HELD IN STEAM FOR DETERMINING THE UPPER

FIXED POINT OF THERMOMETER?

Ans: Because the steam is pure and has specific melting point. If the reading is taken

from the water, it may not accurate as water may not be pure.

Q43: WHAT COULD CAUSE THE POINTER TO AT POSITION BELOW 0?

Ans: By reversing the polarity..

Q44: STATE THE PRECAUTIONS WHILE TAKING A READING FROM

i. Voltmeter

ii. Ammeter

Ans: Check for zero-error, tap them before taking the reading, avoid parallax-error, etc.

Q45: WHAT WILL BE THE EFFECT ON THE CIRCUIT IF THE DIRTY JOCKEY IS

USED?

Ans: A dirty jockey will hinder the flow of current in the circuit BECAUSE the resistance

will increase dramatically.

Q46: HOW WILL YOU “RECORD” READINGS?

Ans: Using the appropriate instruments, the readings are recorded and noted (on a

piece of paper, etc.)

Q47: HOW WILL YOU DISPLAY / REPRESENT YOUR READING?

Ans: The relevant quantities can be tabulated.

Q48: HOW WILL YOU FIND RESULT FROM YOUR REPRESENTED READINGS?

Ans: A graph can be plotted between the relevant quantities and results can be

obtained by deducing data from the graph (e.g. averages, a quantity from the graph,

etc.).

Q49: WHAT PRECAUTIONS WOULD YOU TAKE WHILE TAKING READINGS FROM

MEASURING INSTRUMENTS? (GENERAL PRECAUTIONS)

Ans: Avoid parallax error, wait for a steady reading, remember to add/subtract if there

are zero-errors, etc.

Q50: WHAT IS AN OSCILLATION?

Ans: The process of the bob swinging back and forth steadily and coming back to its

original position.

Q52: HOW WILL YOU NEASURE THE LENGTH OF A PENDULUM?

Ans: Using a meter rule and set-square. Place the meter rule close to the thread and

note the length of the upper and lower ends of the pendulum (l1 and l2). The length l is

calculated by l2 - l1.

Q53: WHAT IS THE USE OF SET SQUARE?

Ans: They are used to allign the ruler to get the correct reading. They help to avoid

parallax errors.

Q55: WHAT IS A MEASUREMENT?

Ans: The size, amount of degree of a physical quantity.

Q56/57: What is an accurate/precise reading?

Ans: Accuracy - the measure of how close you are to the true answer.

Precision - the measure of how closely all your individual measurement match each

other.

Q58/59/61: Define responsiveness, range and sensitivity of a thermometer.

Ans: Range - The minimum and maximum temperatures that the thermometer can

measure.

Sensitivity - It is the length of increase of the liquid per degree rise in temperature.

Responsiveness - How quickly the thermometer can register a change in temperature.

Q60/62: How can we increase the responsiveness, range and sensitivity of the

thermometer?

Ans:

To increase range:

(a) make the thermometer stem longer

(b) make the bore(capillary) bigger

(c) use a liquid with a lower expansivity

To increase sensitivity:

(a) make the bore smaller

(b) use a bigger bulb

(c) use a liquid with a higher expansivity

To increase responsiveness:

(a) use a thin glass bulb

(b) use a liquid that conducts heat better

Q63: WHY THE BORE OF CAPILLARY TUBE IS UNIFORM?

Ans: This improves the thermometer's sensitivity (by giving a large change in length of

the mercury thread for a small change in temperature).

Q64: WHY THE WALLS OF LONG TUBE ABOVE THE BULB ARE MADE THICK?

Ans: Acts as a magnifying glass to easily read the mercury thread in the stem.

Q65: WHAT IS THE ADVANTAGE OF SMALL SIZE OF THERMOMETER?

Ans: It makes it cheap to produce, portable, etc.

Q66: WHY THE MERCURY IS CONTAINED IN A THIN-WALL GLASS BULB?

Ans: This allows for rapid conduction of heat through the thin glass wall to the mercury

contained in the bulb.

Q67: WHAT IS THE PUPOSE OF CONSTRICTION IN THE CLINICAL

THERMOMETER?

Ans: The constriction prevents mercury from flowing back into the bulb.

Q68: WHAT DOES THE STATEMENT MEAN, THAT THE SCALE OF

THERMOMETER IS LINEAR?

Ans: It is the uniform expansion of liquid to temperature.

Q69: WHY THE CROSS-SECTION OF THE STEM OF THERMOMETER IS PEAR-

SHAPED?

Ans: This acts as a magnifying glass in one direction for easy reading of the mercury

thread.

Q. What factors to consider before measuring something?

Ans: The magnitude should not exceed the limit of the instrument, and the instrument

must be sensitive enough to detect a meaningful measurement.

Q. When iron fillings are used, why must the current be large?

Ans: So that the field is stronger and hence the field can be detected.

Q. Why must smaller fillings be used?

Ans: So that the weaker magnetic fields are also shown.

Q. Why must the oscillations be counted from center of swing?

Ans: The chain is moving the fastest at the center of swing.

Q. Suggest a suitable number of oscillations, with reason.

Ans: 20. The time for one oscillation is too short to obtain an accurate reading and so 20

oscillations are timed instead.

Q. Why is the reading in a pendulum repeated?

Ans: This will help ensure a more accurate average value for one oscillation (T).

Q. Why is oil stirred during heating?

Ans: To give uniform heating to the mixture.

Q. Why is the oil heated gently?

Ans: So that an equal change in the temperature will result in a small change of

temperature in the oil.

Work, Energy and Power

1. A man weighs 600 N. He runs up stars of total height 4 metres in 3 seconds.

How much power is exerted by the man?

7200 W

450 W

800 W

2400 W

Power is calculated using 

2. A bullet strikes a fixed target and is brought to rest. The main energy changes

when this happens are:

kinetic to sound and internal energy

potential to sound and internal energy

kinetic to potential and sound

potential to sound and heat

3. What can be used as the unit of energy?

volt ampere

newton per metre

watt second

volt per coulomb

4. The diagram shows a material with dimensions 5 cm   4 cm   2 cm. It has a

mass of 100g.

What is the density of the material?

10 

2.5 

5.0 

0.40 

Density is calculated using this equation:  , where m is the mass and V is the

volume

5. Inertia is the resistance of a object to any change in its state of motion,

including a change in direction. Which property is a measure of the body’s

inertia?

Mass

Volume

Density

Weight

6. Which of the following about energy is false?

Energy has to be supplied when a boy swings his arms during exercise

Energy has to be supplied when a man bends an iron bar

Energy has to be supplied when a helicopter lifts a passenger off the ground

Energy has to be supplied when a chair supports a man sitting on it

7. Consider a stationary box at height x. The block is lifted by a student such that

it comes to a rest at higher height y.

Consider the following discussion between two students:

Student 1: I exert an upward force on the box, which moves upward, so I do

positive work on the box. The Earth exerts a downward force, so it does negative

work on the box. The box begins and ends at rest, so its kinetic energy hasn’t

changed. That means that the net work on the box is zero, so the work on the box

by my hand and the work on the box by the Earth must have the same absolute

value.

Student 2: But the box has moved upward, so its potential energy has increased.

That means that the net work on the block must be positive, so the work on the

box by your hand must be greater than the work on the box by the Earth.

What can you say about the reasoning given by the two students?

They are both incorrect.

Student 2 is correct and student 1 is incorrect.

Student 1 is correct and student 2 is incorrect.

They are both correct.

8. Ten identical steel balls, each of mass 27 g, are immersed in a measuring

cylinder containing 20 cm3 of water.

The reading of the water level rises to 50  .

What is the density of the steel?

9.0 

8.1 

0.90 

13.5 

The volume of the ten steel balls is 50   – 20   = 30  . Density is calculated

using  .

9. When a nucleus of Uranium-235 absorbs a neutron, nuclear fission occurs. In

a typical reaction, the total mass decreases by   kg.

Given that the speed of light c is   m/s, approximately how much energy is

released?

 

Hint: (Use Einstein’s mass equivalence equation:  )

 J

 J

 J

 J

Just plug in the values into the Einstein’s mass energy equation.

10. A pendulum is released from rest and undergoes simple harmonic motion (its

oscillating). The starting point of the pendulum is point A and the lowest point of

the oscillation is point B. By comparing the pendulum’s state at the point A and

point B of the oscillation, what can you say about the

1. total energy of the Earth-pendulum system and

2. the total energy of the system consisting of the pendulum only

 

(Neglect air resistance)

The total energy of the Earth-pendulum system is higher at A. The total

energy of the system consisting of the pendulum is the same at both points.

The total energy of the Earth-pendulum system is the same at both points. The

total energy of the system consisting of the pendulum is higher at A.

The total energy of the Earth-pendulum system is the same at both points. The

total energy of the system consisting of the pendulum is the same at both points.

The total energy of the Earth-pendulum system is the same at both points. The

total energy of the system consisting of the pendulum is higher at B.

There are no external forces on the Earth-pendulum system. Hence, the total energy of

the Earth-pendulum system is unchanged. The Earth is exerting a force (external

force) on the system consisting of the pendulum only, hence the total energy increases

as the pendulum swings from A to B.

11. A box X full of large granite rocks is weighed. An identical box Y full of small

granite chippings is then weighed.

Which box weighs more and why?

Y ; Density of a chipping is greater than a rock

Y ; There is less air in box Y

X ; There is more air in box X

X ; Density of a chipping is less than a rock

Since there is less air in box Y, the volume of chippings will be higher than in box X.

Since the density of chipping is higher than the density of air, box Y will be heavier.

12. A teacher carries a stack of books weighing a total of 30N through 2m. What

is the work done by the teacher?

15 J

60 J

50 J

600 J

Work done = Force (in Newtons) X distance moved in the direction of the force (in

meters)

13. An object is lifted at constant speed through a distance h metres above the

ground in t seconds. The potential energy gained by the object is equal to

work done on the object

work done on the object minus kinetic energy of the object

work done X time

force acting on the object

14. Which statement is correct about the position of the centre of gravity of a

uniform solid?

The centre of gravity of a uniform solid

is fixed and may be outside the body.

is fixed and on the solid itself.

depends on the density of the solid.

depends on the mass of the solid.

15. In a laboratory on Earth, experiments show that an object has a mass of 2 kg

and a weight of 20 N. The same experiments are then brought to the Moon,

where the gravitational field strength is less than on the Earth.

Are the mass and weight of the object the same, or less, than before?

same mass, same weight

Less mass, less weight

same mass, less weight

less mass, same weight

Mass is never changed when moving to a different place with a different gravitational

strength.

16. Which energy changes take place when a pedalling cyclist uses a generator

(dynamo) to light his bicycle lamp?

electrical   chemical   kinetic   light

kinetic   chemical   light   electrical

chemical   kinetic   electrical   light

light   electrical   kinetic   chemical

17. Ali uses a 3 kW heater and a 100 W lamp together for a certain period of

time. During this time, the lamp uses 0.5 kWh of energy. How much energy is

used by the heater during this same period?

150 kWh

3 kWh

15 kWh

30 kWh

Energy = Power X Time. Since the lamp uses 500 Wh, the period of time is 5 hours.

You can use the equation to calculate the amount of energy used by the heater in 5

hours.

18. A car is driven along a level road. The total energy input from the petrol is 60

kJ, and the car wastes 45 kJ of energy.

What is the efficiency of the car?

25 %

75 %

15 %

45%

Efficiency is calculated by 

19. A boy, who weighs 50 N, runs up a flight of stairs 6.5 m high in 7 seconds.

How much power does he develop?

 W

 W

 W

 W

Power is calculated using 

1c 2a 3c 4 b 5a 6d 7c 8 a 9a 11b 12b 13b 14 a 15 c 16 c 17 c 18 a 19 d

Forces & Turning Effect Of Forces

Note:The quiz randomly pulls 10 questions from a pool of questions. Hence, you can

refresh the page and try the quiz again after completion for a new set of 10 questions.

1. A load is to be moved using a wheelbarrow. The total mass of the load and wheelbarrow is 60 kg. The gravitational field strength is 10 N/kg.

What is the size of force F needed just to lift the loaded wheelbarrow?

 350 N

 840 N

 600 N

 430 N

2. A girl uses paper clips to balance a toy bird on her finger as shown.

What is the effect of the paper clips?

 They help to lower the centre of mass below her finger.

 They help to raise the centre of mass to her finger.

 They do not affect the centre of mass but increase the weight.

 They help to raise the centre of mass above her finger.

3. A car is travelling at constant speed along a road and discovers that a thin sheet of ice has formed on the

road. Fearing for his safety, the driver applies the brakes to stop the car. Compared to braking on a dry

road, what may happen?

 The car slows down more quickly because of the greater friction between the

tyres and the road.

 The car speeds up at first because of the reduced friction between the tyres and

the road.

 The car takes longer to slow down because of the reduced friction between the

tyres and the road.

 The car takes longer to slow down because the thinking distance of the driver is

greater.

4. The graph shows how the length of the spring varies with the load. A load is hung on the spring, which

causes the spring to extend by 4 cm. What is the balance reading?

 

 15 N

 20 N

 10 N

 5 N

5.

 

What is the resultant force?

 Magnitude: 21N Direction: XZ

 Magnitude: 15N Direction: WY

 Magnitude: 15N Direction: XZ

 Magnitude: 15N Direction: ZX

6. A body is moving in a straight line under the action of a constant force. What

change will occur to the body?

 Change in acceleration

 Change in inertia

 Change in mass

 Change in kinetic energy

7. Why does an object falling in the Earth’s gravitational field reach a steady velocity?

 Air resistance increases with the increase of velocity

 The Earth’s gravitational field decreases as it falls

 The weight of the object increases as it falls

 The mass of the object remains constant

8. A spring extends by 4 cm when 10 N is suspended from it. Two of these springs are

used as shown to carry a 30 N load.

What is the extension of each spring?

 12 cm

 6 cm

 8 cm

 4 cm

9. An object of mass 2 kg is pushed along a horizontal flat surface. The friction force

is measured to be 4 N. When the same object is pushed along the same surface with a

force of 10 N, it moves with a constant

 acceleration of 

 speed of 5 m/s

 acceleration of 

 speed of 3 m/s

10. When t = 0, a constant horizontal force is applied to a body initially at rest on a

smooth horizontal table.. Which of the following quantities will not change during the

time period t > 0?

 The kinetic energy of the body

 The velocity of the body

 The displacement of the body

 The acceleration of the body1a, 2a 3b 4b 5c 6 d 7a 8b 9c 10 d

 MCQs For Speed, Velocity & Acceleration

1. A boy throws a ball up into the air. The initial velocity of the ball was 6 m/s.

Taking  and assuming there was no air resistance, find

(a) The maximum height the ball reaches,

(b) The velocity of the ball when it reaches the boy’s hand,

(c) The time the ball is up in the air

[Take the upwards motion to be negative]

 -1.8 m, 6 m/s, 0.6 s

 1.8 m, 6 m/s, 0.6 s

 -1.8 m, 6 m/s, 1.2 s

 1.8 m, 6 m/s, 1.2 s

2. The motion of a toy car is measured by a ticker tape timer as shown in the diagram

below. Which of the following statements best describe its motion?

 The toy car was first traveling at a constant speed. It then sped up and then

slowed down before coming to a stop eventually.

 The toy car was first traveling at a constant speed. It then accelerated and traveled

at a higher constant speed before stopping eventually.

 The car was accelerating at first before slowing down and stopping eventually.

 The toy car was first traveling at a constant speed. It then accelerated and traveled

at a higher constant speed before decelerating and coming to a stop eventually.

3. A ticker tape timer produces 50 dots on a tape in 1 second. Below is a portion of the

tape:

 

How long was the time taken to produce the above strip?

 1 second

 0.02 seconds

 0.20 seconds

 0.22 seconds

4. The diagram below shows a speed-time graph of a vehicle. Determine its distance

traveled and its acceleration at the 5th, 11th and 19th second.

 25, 60 and 40 m -2, 0 and 

 50, 60 and 80 m 10, 10 and 

 50, 60 and 40 m 2, 10 and 

 25, 60 and 40 m 2, 0 and 

5. This is a distance-time graph of a moving car (not drawn to scale).

 

Which of the following depicts its speed-time graph?

http://cdn.miniphysics.com/wp-content/uploads/2015/04/speed-time-graph-1.png

 

 1

 None of the above

 3

 2

6. A train travelling at an average speed of 60 km/hr comes to a complete stop in 20

minutes’ time. What is its deceleration?

 

 

 

 

7. A car travelling at 70 km/hr slows down to 50 km/hr in 30 minutes. What is its

acceleration?

 

 

 

 

8. The diagram below shows a speed-time graph of a vehicle. Which of the following

are the corresponding distance-time and acceleration-time graphs (not drawn to

scale)?

 

 

 

 3, 4

 1, 2

 3, 2

 1, 4

9. A racing car accelerates uniformly through three gear changes with the following

average speeds:

 for 2.0 s

 for 2.0 s

 for 6.0 s

What is its average speed?

 

 

 

 

10. A vehicle travelling at 40 m/s accelerates uniformly at   for 20 seconds.

What is its final speed?

 60 m/s

 -100 m/s

 100 m/s

 140 m/s

11. A ball is thrown downwards at a velocity of 8 m/s and bounces upwards. Which of

the following is its velocity-time graph?

[Assume no air resistance or energy lost and take downwards motion as positive

direction]

 

 

 

4) None of the above

 

 2)

 4)

 3)

 1)

12. A boy jogs around his neighbourhood for 1.5 hours as shown in the following

diagram:

(a) What is his displacement?

(b) What is the total distance he jogged?

(c) What is his average speed?

 (a) 14 km, (b) 0 km and (c) 14 km/hr

 (a) 0 km, (b) 14 km and (c) 14 km/hr

 (a) 14 km, (b) 0 km and (c) 9.33 km/hr

 (a) 0 km, (b) 14 km and (c) 9.33 km/hr

13. A bicycle was travelling at    when it applied its brakes and decelerated at a

rate of  .

(a) How long will it take before it comes to a stop? (b) How far will it travel before

stopping?

 5 s, 40 m

 5 s, 20 m

 4 s, 40 m

 4 s, 20 m

14. Acceleration is:

 

 

 

 

(a) 

-20s = 36

s = – 1.8 m

Since height is a scalar quantity, the maximum height the ball reaches is 1.8 m. The

negative sign is because the ball is thrown upwards. Had the question asked about the

displacement of the ball when it reaches the maximum height, the answer would be -

1.8 m.

(b) Acceleration is the same during the upwards and downwards motion. If the

velocity of the ball changes from  6 m/s to 0 m/s on the way up, the velocity of the

ball will change from 0 m/s to 6 m/s on the way down. Hence, the velocity of the ball

when it reaches the boy’s hand is 6 m/s.

(c) v = u + at

0 = -6 + 10t

10t = 6

t = 0.6 s

Since the ball would take the same amount of time to travel upwards and downwards,

the total time would be 1.2 s.

2d 3d 4( 24, 60 and 40m)c 5a 6d 7Acceleration= change in velocity over time taken ()

= final velocity – initial velocity over 0.5hr

= 

= 

= 

Note: The negative sign means that the car is decelerating. So, if the question is

asking what is the car’s deceleration, the answer should be  .

9 48ms c 10 140m/s

100 = v-40

v = 100+40

= 140 m/s

11 a 12d 13c (a)  v = u + at

0 = 20 + (-5t)

5t = 20

t = 4 s

(b)  

= 40 m

or

 

10s = 400

s = 40 m

14d 8 (1,2)