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TWGHs Kap Yan Directors' College
First Term Test
2015-2016
Physics
Form 4
/ 70
Time allowed: 1.5 hours
Total marks: 70
Date: 11 Nov 2015
LPK
Name : _______________________________
Class: ________
Class no. : ________
INSTRUCTIONS
1. This paper consists of two sections, Section A and Section B. Section A consists of Structured-type
questions. Section B consists of multiple choice questions.
2. Answer ALL questions.
3. Answers to Section A should be written in the spaces provided in this Question-Answer Book. Answers to
Section B should be marked on the Multiple-choice Answer Sheet.
4. The diagrams in this paper are NOT necessarily drawn to scale.
5. The following contains a list of data, formulae and relationships which you may find useful.
List of data, formulae and relationships
Data
g = 9.81 m s2 (close to the Earth)
acceleration due to gravity
Rectilinear motion
For uniformly accelerated motion:
B1.
v
=
s
=
v2
=
F =m
u + at
1
ut + at 2
2
u2 + 2as
v  p
=
t  t
Mathematics
Equation of a straight line
y = mx + c
Arc length
= r
Surface area of cylinder
= 2rh + 2r2
Volume of cylinder
= r2h
Surface area of sphere
= 4r2
Volume of sphere
4
= πr 3
3
force
P.1
Section A : Structured-type Questions (30 marks)
1. (a) A block of mass 5 kg is placed on a rough surface as shown in Figure 1. A horizontal force F of 5 N is
applied on it. The block moves at a constant velocity of 1 m s1.
Figure 1
(i) Find the friction between the block and the table.
(1 mark)
__________________________________________________________________________________
__________________________________________________________________________________
(ii) Calculate the acceleration of the block if F is increased to 10 N.
(2 marks)
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
(b) The 5 kg block and another 10 kg block are then placed together on a smooth surface as shown in
Figure 2. A 75 N force is applied horizontally towards the right against the 5 kg block.
Figure 2
(i) Calculate the acceleration of the blocks.
(2 marks)
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
(ii) Calculate the speed of the blocks after 2 s if the blocks are initially at rest.
(2 marks)
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
P.2
(iii) Calculate the net force acting on the 5 kg block.
(2 marks)
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
2. An oil tanker has a mass of 180 000 tons (1 ton = 1000 kg). It can reach a maximum speed of 25 km h -1.
When the tanker is in full speed, it takes a very long distance of 2.5 km for the tanker to stop completely.
(a) Explain in terms of inertia, why it takes such a long distance for the oil tanker to stop.
(2 marks)
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
(b) Assuming that the deceleration is uniform, calculate the deceleration and the time it takes for the tanker
to stop.
(3 marks)
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
(c) What is the average decelerating force acting on the tanker?
(2 marks)
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
P.3
3. A golf ball of mass 0.046 kg initially at rest is struck by a putter. The golf ball moves a distance of 5 cm
during which it remains in contact with the putter. At the moment the ball leaves the putter, it moves with a
velocity of 10 m s-1.
10 m s1
5 cm
(a) Find the average acceleration of the golf ball when it is in contact with the putter.
(2 marks)
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
(b) Find the average force exerted by the putter on the golf ball.
(2 marks)
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
(c) A student says that if the mass of the ball is larger, the speed of the ball after leaving the putter is
higher. Explain whether the student is correct.
(3 marks)
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
P.4
4. The velocity-time graph of a ping-pong ball falling in air is as shown in the following figure. The ball has a
mass of 2 g and is released at time t = 0. The air resistance is NOT negligible in this question.
ping-pong
ball
Figure 4
(a) Draw a free body diagram to show all the forces acting on the falling ping-pong ball in Figure 4 above.
(2 marks)
(b) Is the acceleration at t = 1s greater than, equal to or smaller than the acceleration at t = 2s? Explain
briefly.
(2 marks)
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
(c) What is the terminal velocity of the ball?
(1 mark)
__________________________________________________________________________________
__________________________________________________________________________________
(d) At a certain instant, the acceleration of the ball is 5 m s-2, find the magnitude of the air resistance acting
on the ball.
(2 marks)
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
P.5
Section B: Multiple Choice Questions (40 marks)
1. There are 3 forces acting on an object at rest. Which of the following is not a possible combination of the
forces?
A. 3 N, 4 N and 6 N
C. 2 N, 4 N and 6 N
B. 1 N, 2 N and 4 N
D. 5 N, 5 N and 2 N
2. A trolley moving at a speed of u at A uniformly accelerates along a
straight line ABC. Its speed is v when it reaches C. If the ratio of AB
to BC is 3:1, what is the speed of the trolley at B?
3
3
u 2  3v 2
A.
B.
C.
D.
v  u 
v  u 
4
4
2
3u 2  v 2
2
3. Which of the following objects have zero net force acting on them?
(1) The moon orbiting around the Earth
(2) A bob suspended by a string, and remaining at rest
(3) A box sliding down an inclined plane at a constant velocity
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
4. The figure shows the velocity-time graph of a car. The average
velocity of the car from time t = 0 to t = 25 s is
A. 13 m s-1
C. 17 m s-1
B. 15 m s-1
D. 20 m s-1
5. Which of the following are vectors?
(1) Speed
(2) Force
(3) Displacement
A. (1) and (3) only
B. (1) and (2) only
C. (2) and (3) only
6. Which of the following objects has the largest inertia?
A.
B.
C.
D.
A 4.2 g bullet moving at a speed of 950 m s-1
A 15 kg bicycle moving at a speed of 8 m s-1
A 2000 kg car moving at a speed of 20 m s-1
A 7000 kg elephant moving at a speed of 2 m s-1
7. Four forces act on an object of mass 0.25 kg as shown.
What is the magnitude of the acceleration of the object?
A. 2.0 m s-2
B. 4.0 m s-2
C. 5.0 m s-2
P.6
D. 7.6 m s-2
D. (1), (2) and (3)
8. A toy train driven by a locomotive is travelling on straight horizontal rails with a uniform speed as shown.
At a certain instant, the cable between the locomotive and the compartment breaks and the compartment
gradually slows down.
locomotive
compartment
Which of the following statements about the compartment is/are correct?
(1) After the cable breaks, no net force is applied on the compartment.
(2) The acceleration of the compartment is in the opposite direction to its velocity.
(3) After the cable breaks, the compartment tends to travel in the opposite direction to that before.
A. (2) only
B. (3) only
C. (1) and (2) only
D. (2) and (3) only
9. On the roof of a house, a stone is thrown vertically upwards with an initial speed of 10 m s−1 at time t = 0 s.
The stone touches the ground at t = 3.00 s. What is the total distance travelled by the stone?
A. 5.10 m
B. 14.1 m
C. 19.2 m
D. 24.3 m
10. Y has a linear relationship with time as shown. Y may represent
(1) the speed of a body starting from rest under a constant force.
(2) the distance travelled by a body at constant speed.
(3) the acceleration of a body falling from rest.
A. (1) only
C. (1) and (2) only
B. (3) only
D. (2) and (3) only
11. A 3 kg block is pulled along a horizontal table by a force of 20 N
as shown.
If the block is accelerating at 2 m s-2, find the friction acting on
the block.
A. 4.0 N
C. 14.0 N
B. 11.3 N
D. 17.3 N
12. Two drivers of cars A and B driving on a straight horizontal
road see an obstacle at time t = 0. They then apply the brakes to
stop the car with uniform decelerations. The velocity-time graph of
the two cars is shown in the figure. Which of the following
statements is/are correct?
(1) Driver of car A has a shorter reaction time.
(2) A and B stop at the same time.
(3) Car A has a smaller deceleration.
A. (1) and (2) only
C. (2) and (3) only
B. (1) and (3) only
D. (1), (2) and (3)
P.7
20 N
30
block
13. A ball is thrown vertically upwards at the roof of a building. It hits the ground at time t = 3.6 s. The motion
of the ball is shown in the v-t graph. What are the height of the building and the total distance travaelled by
the ball?
A.
B.
C.
D.
The height of the building
18 m
20.25 m
18 m
20.25 m
Total distance traveled by the ball
20.25 m
20.25 m
22.5 m
22.5 m
14. A car starts at a point A and travels along a circular path of radius 30 m. After 15 s, the car returns to point
A. Find the average speed of the car within this period of time.
A.
B. 2 m s-1
zero
C. 6.3 m s-1
D. 12.6 m s-1
15. A plane starts from rest and accelerates at 2 m s-2. If the minimum take-off speed is 60 m s-1, find the
minimum distance travelled by the plane before it takes off.
A. 450 m
B. 900 m
C. 1800 m
D. 3600 m
16. A stone is thrown vertically upwards at an initial velocity u. What is the velocity of the stone when it is
half way up?
A. u
B.
u
2
C.
u
D.
3
u
2
17. The figure shows the variation of the velocity of an object with time.
Which of the following statements is/are correct?
(1) The average velocity of the first 20 seconds is 15 m s-1.
(2) The total displacement travelled during the first 10 seconds is
112.5 m.
(3) The acceleration of the first 5 seconds is 3 m s-2.
A. (1) only.
C. (2) and (3) only.
B. (3) only.
D. (1), (2) and (3).
18. The figure shows a block acted on by two forces on a rough horizontal
surface. The two forces are in opposite directions with magnitudes F
and 4 N respectively. If the maximum value of F for the block remaining
at rest is 10 N, what is the net force on the block when F is removed?
A. zero
B. 2 N
C. 4 N
D. 6N
P.8
19. Two blocks X and Y are placed on a horizontal frictionless surface as shown. Two horizontal forces F 1
and F2 are applied on X and Y respectively. Then two blocks move to the right with constant acceleration a
since F1 > F2. Given that the mass ratio of the two blocks is 2:3, what is the force acting on Y by X?
A.
2( F1  F2 )
5
B.
3( F1  F2 )
5
C.
3F1  2 F2
5
D.
F1  F2
5
20. A book and a stone, both have the same mass of 1 kg, are released from rest from 10th floor of a building.
Eventually, the stone reaches the ground first. Which of the following statements about the above
phenomenon is/are correct?
(1) The net forces acting on both objects are always the same.
(2) The stone has a greater inertia.
(3) The average air resistance acting on the book is greater.
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
21. Which of the following statements about mass and weight are correct?
(1) Mass is a scalar and weight is a vector.
(2) The mass of an object is a constant but its weight depends on its location.
(3) The S.I. unit of mass and weight is kilogram.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
22. During a high jump, when the jumper reaches the highest position,
(1) his vertical speed is zero.
(2) the net force acting on him is zero.
(3) his acceleration is zero.
A. (1) only
B. (3) only
C. (1) and (2) only
D. (2) and (3) only
23. A toy car of mass 0.8 kg is travelling on a straight path. The graph below shows how the net force F acting
on it varies with time t. The toy car is initially at rest.
Which of the following statements about the toy car is/are correct?
(1) It accelerates from t = 0 to 2 s.
(2) It decelerates from t = 2 to 5 s.
(3) It remains at rest from t = 5 to 6 s.
A. (1) only
B. (1) and (2) only
C. (2) and (3) only
P.9
D. (1), (2) and (3)
24. A hydrogen balloon of mass 50 g is attached to the ground by a piece of string as shown. When the string
breaks, the balloon rises up with an acceleration of 2 m s-2. What is the tension in the string before its
breaks?
A. 0.05 N
B. 0.1 N
C. 0.55 N
D. 0.6 N
F1
25. Three forces of magnitudes F1, F2 and 20 N act on an object as shown. If the
object is in equilibrium, find F2.
30
A.
B.
C.
D.
10 N
11.5 N
17.3 N
20 N
F2
20 N
26. Two blocks A and B of masses 4 kg and 5 kg respectively are connected by a light inextensible string. The
blocks rest on a smooth horizontal surface. A force of 3 N is applied to block A as shown. Find the tension
in the string connecting the two blocks.
\
A. 0.333 N
B. 1.33 N
C. 1.67 N
D. 3 N
27. An object M accelerates in the upward direction only. Find the magnitude of
F.
A. 5.77 N
B. 8.66 N
C. 9 N
D. 10 N
28. An object of mass of 1 kg is at rest on a smooth horizontal surface. A constant force of 4 N acts on the
object for 2 s and is then removed. What is the speed of the object after 3 s?
A. 0.8 m s-1
B. 2 m s-1
C. 4 m s-1
P.10
D. 8 m s-1
29. An object is travelling along a straight line. Its displacement s varies with the square of time t2 as shown.
Which of the following statements are correct?
(1) The object is initially at rest.
(2) The acceleration of the object is 2 m s-2.
(3) At time t = 1 s, the velocity of the object is 2 m s-1.
A. (1) only
B. (1) and (2) only
C. (2) and (3) only
D. (1), (2) and (3)
30. An experiment is carried out by an astronaut on the surface of the Moon. A coin and a feather are
dropped at the same instant from the same height. Which statement is correct?
A. They fall together, taking a longer time than the coin would in falling from the same height on
Earth.
B. They fall together, taking a shorter time than the coin would in falling from the same height on
Earth.
C. The coin falls faster than the feather, but both take a longer time than if they were falling from the
same height on Earth.
D. The coin falls faster than the feather, but both take a shorter time than if they were falling from the
same height on Earth.
31. A bullet of mass 0.02 kg travelling horizontally at 100 m s-1 is stopped by 0.1 m of concrete. What is the
resistive force on the bullet by the concrete?
A. 2 N
B. 10 N
C. 100 N
D. 1000 N
32. Which of the following statements about speed, velocity and acceleration is/are correct?
(1) Velocity and acceleration are vectors.
(2) An object traveling at constant speed can be accelerating.
(3) Change in velocity and acceleration must be in the same direction.
A. (1) only
C. (2) and (3) only
B. (3) only
D. (1), (2) and (3)
P.11
End of Paper
F.4 Physics First Term Test (15-16) Marking Scheme
1. (a) (i)
(ii)
(b)
(i)
The block mo ves at a constant velocity.
 frictional force = applied force = 5 N
By Newton’s second law of motion,
F = ma
10  5 = 5a
a = 1 m s2
75
F

Acceleration of the blocks 
= 5 m s2
m
10  5
(ii)
v = u + at
= 0 + 5 x 2 = 10 m/s
(iii) Net force acting on the 5-kg block = ma = 5  5 = 25 N
2.
1A
1M for 10-5
1A
1M for
F/m+1A
1M for v =
u+at, 1A
1M+1A
(a) As the oil tanker has a very large mass (1A), it has a very large inertia and is therefore very
‘reluctant’ to change its state of motion (1A).
25  1000
(b) Given that v = 0, u =
= 6.94 m s-1 and s = 2500 m.
60  60
Applying v2 - u2 = 2as, the deceleration of the tanker is
v 2  u 2 0 2  6.94 2
(1A for a)
a

 9.65 10 3 m s 2
2s
2  2500
Applying v = u + at, the time required is
v u
0  6.94
(1M+1A)
t

 720 s
a
 9.65 10 3
(c)
Applying F = ma, the average decelerating force is
F  180 000 1000  9.65 10 3  1.74 10 6 N
(1M+1A)
3. (a) Applying v 2  u 2  2as , the average acceleration of the golf ball is
v 2  u 2 10 2  0 2
(1M for using v 2  u 2  2as +1A)
a

 1000 m s 2
2s
2  0.05
(b) Applying F  ma , the average force is
(1M+1A)
F  0.046 1000  46 N
(c) If the mass is larger, the acceleration is smaller if the force is unchanged. So the speed of the ball
after leaving the putter is smaller. So the student is incorrect.
(3A)
4.
(a)
Air resistance
Weight
(b)
(1A for weight)
(1A for air resistance)
The acceleration at t = 1s is greater than the acceleration at t = 2s.
(1A)
It is because the slope of tangent (or slope) at t = 1s is greater than that at t = 2s.
(1A)
(c) 8.8 m s-1
(1A)
(d) F = ma
mg  f  ma where f is the air resistance
(1M for mg – air resistance)
0.002 x 9.81 – f = 0.002 x 5
f = 0.00962 N
(1A)
-------------------------------------------------------------MC
1-5
BCCBC
6-10 D A A D C
11-15 B A C D B
16-20 D D A C B
21-25 A A A B B
26-30 C D D A A
31-32 D D