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HKCEE 1999 - 2003
PHYSICS - MC Questions
Mechanics
(1999-CE-PHY II - 1)
1.
A man takes 30 s to walk from point A to point B along a straight road,
where AB = 120 m. He then takes 20 s to run backwards to a point C, where
BC = 100 m. Find the average speed of the man for the whole journey.
A.
B.
C.
D.
E.
0.4 m s-1
2.0 m s-1
4.0 m s-1
4.4 m s-1
4.5 m s-1
(1999-CE-PHY II - 2)
2. A 2 kg steel sphere and a 1 kg wooden sphere are initially held at the same
level above ground and then released from rest simultaneously. Assume air
resistance is negligible. Which of the following statements about the two
spheres at any instant before they reach the ground is/are correct ?
(1)
(2)
(3)
The speed of the two spheres are equal.
The accelerations of the two spheres are equal.
The gravitational forces acting on the two spheres are equal.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(1999-CE-PHY II - 3)
3.
A car starts from rest and travels along a straight road. The accelerationtime graph of the car is shown above. Which of the following graphs shows
the variation of the velocity v of the car with time t ?
A.
B.
C.
D.
E.
(1999-CE-PHY II - 4)
4.
A block is sliding down a friction compensated runway as shown above.
Which of the following statements is/are correct ?
(1)
(2)
(3)
The speed of the block is increasing.
The normal reaction acting by the runway on the block is increasing.
The net force acting on the block is zero.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(1999-CE-PHY II - 5)
5.
A light rope is fixed at two poles with the ends A and B at the same level. A
T-shirt of weight 2 N is hung at the midpoint C of the rope. The rope
depresses such that ∠ACB = 150°. Find the tension in the rope.
A.
B.
C.
D.
E.
1.0 N
2.0 N
3.9 N
7.7 N
It cannot be determined since the length of the rope is not given.
(1999-CE-PHY II - 6)
6.
A solid rectangular block is of dimensions 4 cm x 4 cm x 5 cm. The block
exerts a pressure PX on horizontal ground when it stands on face X as shown
above. Let PY and PZ be the pressures exerted by the block on horizontal
ground when the block stands on faces Y and Z respectively. Which of the
following relations is correct ?
A.
B.
C.
D.
E.
PX =PY =PZ
PX <PY <PZ
PX <PY =PZ
PX >PY >PZ
PX >PY =PZ
(1999-CE-PHY II - 7)
7. A motor car of mass 2000 kg accelerates from rest at 3 m s-2 for 4 s on a
straight road. Find the average useful output power of the engine of the car.
A.
B.
C.
D.
E.
24 kW
36 kW
72 kW
144 kW
240 kW
(1999-CE-PHY II - 8)
8.
A rocket is initially at rest in space. It then explodes and breaks in to two
parts which move in opposite directions. If the mass of the rear part is larger
than that of the front part, which of the following statements is correct ?
A.
B.
C.
D.
E.
The speeds of the two parts are equal.
The speed of the rear part is higher than that of the front part.
The magnitudes of the momentum of the two parts are equal.
The magnitude of the momentum of the rear part is larger than
that of the front part.
The kinetic energies of the two parts are equal.
(1999-CE-PHY II - 9)
9.
A uniform rod of length  is pivoted at a point

from one of its ends.
4
Two forces 14 N and 3 N act on its two ends as shown above. If the rod is in
equilibrium, find the weight of the rod. (Assume the weight of the rod acts
through its midpoint.)
A.
B.
C.
D.
E.
2.5 N
5N
8N
11 N
17 N
(1999-CE-PHY II - 10)
10.
Which of the following is/are the advantage(s) of using a nutcracker to crack
a nut as shown above ?
(1)
(2)
(3)
The effort required to crack the nut is reduced.
The energy required to crack the nut is reduced.
The distance travelled by the effort in cracking the nut is reduced.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(2000-CE-PHY II - 1)
1. Which of the following physical quantities is not a vector ?
A.
B.
C.
D.
E.
acceleration
displacement
momentum
potential energy
weight
(2000-CE-PHY II - 2)
2. It is said that Galileo Galilei (1564-1642), an Italian scientist, dropped a
small iron ball and a large cannon ball from the top of the Leaning Tower of
Pisa. He found that the two balls reached the ground at almost the same
time.
Which of the following is/are correct deduction(s) from this experiment ?
(1) The two balls fell with the same acceleration.
(2) A body will maintain uniform motion if there is no external force
acting on it.
(3) The gravitational forces acting on the two balls were identical.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(2000-CE-PHY II - 3)
3.
A racing car accelerates from rest to a speed of 100 km h -1 in 3.2 s. Find the
average acceleration of the car.
A.
B.
C.
D.
E.
4.34 m s-2
8.68 m s-2
15.63 m s-2
31.25 m s-2
112.50 m s-2
(2000-CE-PHY II - 4)
4.
The cars A and B travel along the same straight road. The velocity-time
graphs of the two cars are shown above. Which of the following statements
about the motion of the two cars at time T0 is/are always correct ?
(1)
(2)
(3)
The two cars meet each other.
The two cars are moving with the same speed but in opposite
directions.
Car A is accelerating while B is decelerating.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(2000-CE-PHY II - 5)
5.
An astronaut lands on the moon and finds that his weight is about one-sixth
of that on earth. Which of the following deductions is/are correct ?
(1)
(2)
(3)
If he throws an object upwards on the moon, it will reach a higher level
than throwing the object with the same speed on earth.
If he releases an object on the moon, it will take a shorter time to reach
the ground than releasing the object from the same height on earth.
The maximum weight he can lift on the moon is greater than on earth.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(2000-CE-PHY II - 6)
6.
Three forces of magnitudes F1, F2 and 10 N act on an object as shown above.
If the object is in equilibrium, find F2.
A.
B.
C.
D.
E.
5.0 N
8.7 N
11.5 N
17.3 N
20.0 N
(2000-CE-PHY II - 7)
7.
A block is placed on a rough inclined plane and then projected upwards
along the plane. After reaching the highest point, the block slides down
along the plane. Which of the following graphs shows the variation of the
velocity v of the block with time t ?
A.
B.
C.
D.
E.
(2000-CE-PHY II - 8)
8.
A uniform steel ball lies at rest on a horizontal ground and just touches a
vertical wall as shown above. Which of the following diagrams shows all
the forces acting on the ball ?
(Note : W = gravitational force acting on the ball,
R = normal reaction from the ground,
F = friction acting by the ground on the ball,
N = normal reaction from the wall.)
A.
B.
C.
D.
E.
(2000-CE-PHY II - 9)
9.
A block is placed on a rough horizontal ground and a horizontal force acts
on the block. If the magnitude of the force, F, is increased gradually, which
of the following graphs shows the relation between F and the acceleration a
of the block ?
A.
B.
C.
D.
E.
(2000-CE-PHY II - 10)
10.
The above graph shows the variation of the kinetic energy E of an object
with the square of its velocity v2. What is the momentum of the object when
it is moving at a velocity 4 m s-1 ?
A.
B.
C.
D.
E.
4 kg ms-1
8 kg ms-1
16 kg ms-1
32 kg ms-1
It cannot be determined since the mass of the object is not given.
(2000-CE-PHY II - 11)
11.
A 2 kg block is initially at rest on the ground. A machine is used to pull up
the block as shown above. If the tension in the string is kept at 24 N and the
block reaches a height of 4 m in 2 s, which of the following statements is/are
correct ?
(1)
(2)
(3)
The potential energy of the block is increasing when the block is
rising.
The kinetic energy of the block is increasing when the block is rising.
The average power developed by the machine during the two seconds
is 40 W.
A. (1) only
B. (3) only
C. (1) and (2) only
D. (2) and (3) only
E. (1), (2) and (3)
(2000-CE-PHY II - 12)
12.
A company intends to produce a kind of weighing device as shown above.
The device is held at point X. The position of the counter-weight is adjusted
until the rod AB becomes horizontal. The weight of the object can be read
form the scale calibrated on AB. Which of the following changes can
increases the maximum weight that can be measured by the device ?
(1)
(2)
(3)
A.
B.
C.
D.
E.
moving the string at X towards A
increasing the mass of the counter-weight
increasing the length of the string from which the counter-weight
hangs
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(2001-CE-PHY II - 1)
1.
A car travels along a straight road. The variation of the distance of the car
from a fixed point P on the road with time is shown above. Which of the
following statements is correct ?
A.
B.
C.
D.
E.
2.
The speed of the car is decreasing.
The car is moving towards P.
There is an unbalanced force acting on the car.
The area under the graph denotes the total distance travelled by
the car.
The slope of the graph denotes the acceleration of the car.
(2001-CE-PHY II - 2)
A girl walks along a straight road from a point A to a point B with an average
speed 1 m s-1. She then returns from B to A along the same road with an
average speed 2 m s-1. Find the average speed of the girl for the whole
journey.
A.
B.
C.
D.
E.
zero
0.67 m s-1
1.33 m s-1
1.41 m s-1
1.50 m s-1
(2001-CE-PHY II - 3)
3.
A stone is thrown vertically upwards. Assuming air resistance is negligible,
which of the following statements is/are correct ?
(1)
(2)
(3)
The acceleration of the stone decreases throughout the upward motion.
The net force acting on the stone becomes zero when the stone reaches
the highest point.
The total energy of the stone remains unchanged throughout the
motion.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(2001-CE-PHY II - 4)
4.
A coin is placed on a piece of cardboard resting on a glass as shown above. If
the cardboard is flicked off sharply with a finger, the coin will drop into the
glass. What does this experiment demonstrate ?
A.
B.
C.
D.
E.
The coin will fall with uniform acceleration under the action of
gravity.
The acceleration of the coin is proportional to the applied force.
Action and reaction always occur in pairs.
Momentum is conserved in a collision.
The coin has a tendency to maintain its state of rest.
(2001-CE-PHY II - 5)
5.
A block on a rough horizontal table is acted on by two horizontal forces of
magnitudes 10 N and 2 N as shown. It remains at rest on the table. If the
force of magnitude 10 N is removed, find the resultant force acting on the
block.
A.
B.
C.
D.
E.
zero
2N
6N
8N
10 N
(2001-CE-PHY II - 6)
6.
A uniform plank of weight 450 N rests on two trestles X and Y and a worker
of weight 675 N stands at one end of the plank as shown above. The worker
holds a light basket which contains several packets of goods each of weight
6 N. What is the maximum number of packets he can hold without tilting the
plank ? (Assume the weight of the plank acts through its centre.)
A.
11
B.
12
C.
13
D.
18
E.
19
(2001-CE-PHY II - 7)
7.
A student uses a friction-compensated runway to study Newton’s second law
of motion. The variation of the acceleration a of the trolley with the force F
applied parallel to the runway is shown above. If the experiment is repeated
with the runway making a larger angle of inclination with the horizontal,
which of the following graphs (in dotted lines) represents the expected
result ?
A
.
B
.
C
.
D
.
E
.
(2001-CE-PHY II - 8)
8.
The figure above shows the variation of the force acting on a car driver with
time when the car hits a wall. The driver is not wearing a seat-belt. Which of
the following graphs (in dotted lines) best shows the force acting on the
deriver if he is wearing a seat-belt ?
A.
B.
C.
D.
E.
(For questions 9 and 10.) A man is pulling a suitcase along the horizontal ground
as shown below.
(2001-CE-PHY II - 9)
9. Which of the following pairs of forces is/are action and reaction pair(s)
according to Newton’s third law of motion ?
The gravitational force
The gravitational force
(1)
exerted by the earth on the
exerted by the man on
and
man
the earth
The friction exerted by
The pulling force exerted
(2)
the ground on the
and
by the man on the suitcase
suitcase
The gravitational force
The normal reaction
(3)
exerted by the earth on the
exerted by the ground
and
suitcase
on the suitcase
A. (1) only
B. (3) only
C. (1) and (2) only
D. (2) and (3) only
E. (1), (2) and (3)
(2001-CE-PHY II - 10)
10. If the rope is inclined at angle θ to the horizontal and the tension in the
rope is 100 N, find the work done by the man in pulling the suitcase for a
distance of 5 m along the ground.
A.
B.
C.
D.
E.
500 J
500 sinθJ
500 cosθJ
500
J
sin 
500
J
cos 
(2001-CE-PHY II - 11)
11. A rocket of mass 5000 kg is at rest in space. It then explodes and breaks into
two parts P1 and P2 of mass 1000 kg and 4000 kg respectively. Find the ratio
of the kinetic energy of P1 to that of P2.
A.
1:1
B.
1 : 16
C.
1 : 64
D.
4:1
E.
16 : 1
(2001-CE-PHY II - 12)
12.
The figure above shows a nail being driven into a wooden door with a
hammer. Which of the following statements is/are correct ?
(1)
(2)
(3)
Using a hammer can reduce the work done against the resistance on the
nail by the door.
The force exerted by the nail on the door is larger than that exerted by
the hammer on the nail.
The pressure exerted by the nail on the door is larger than that exerted
by the hammer on the nail.
A.
B.
C.
D.
E.
(1) only
(3) only
(1) and (2) only
(2) and (3) only
(1), (2) and (3)
(2002-CE-PHY II - 1)
1.
The figure above shows the distance-time graphs of two toy cars P and Q
moving along a linear track. Which of the following statements are correct?
(1)
Car P will reach the 20 m-mark first.
(2)
Car P is overtaking car Q at t = 5 s.
(3) The average speed of car P in the first 5 s is smaller than that of car Q.
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
(2002-CE-PHY II - 2)
2.
The figure above shows the variation of the resultant force acting on an object
with time. What physical quantity does the area of the shaded region
represent?
A. acceleration
B. change of momentum
C. work
D. power
(2002-CE-PHY II - 3)
3. A piece of stone is hung from a balloon, which is rising vertically upward. If
the string connecting the stone and the balloon suddenly breaks, which of the
following velocity-time graphs represents the subsequent motion of the stone?
(Note: Velocity pointing upward is taken to be positive.)
(2002-CE-PHY II - 4)
4. The following are statements written by three students about Newton’s first
law of motion.
(1) A stationary object will remain in a state of rest unless acted on by an
unbalanced force.
(2) An object undergoing uniform motion will maintain its motion unless
acted on by an unbalanced force.
(3) An unbalanced force is required to maintain the motion of an object at
uniform velocity.
Which of the above statements is/are correct?
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
(2002-CE-PHY II - 5)
5. Which of the following objects are under the action of an unbalanced force at
the instant shown in the diagrams?
A. (1) and (2) only
B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)
(2002-CE-PHY II - 6)
6.
A block of mass 0.5 kg slides down a rough inclined plane with an
acceleration of 3 ms-2. If the plane is inclined at 30o to the horizontal, find the
friction between the block and the plane.
A. 1 N
B. 1.5 N
C. 2.8 N
D. 4 N
(2002-CE-PHY II - 7)
7. John, of mass 80 kg, is standing on a weighing scale in a lift. At a certain
instant, the reading of the weighing scale is 600 N. Which of the following
statements about John at this instant is/are correct?
(1)
The gravitational force acting on John is 600 N.
(2) The force exerted by the weighing scale on John is 200 N.
(3) John is accelerating downward at a rate of 2.5ms-2.
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
(2002-CE-PHY II - 8)
8.
A block is projected up a smooth inclined plane. Which of the following
graphs shows the variation of the kinetic energy (K.E.) of the block with its
potential energy (P.E.) during the upward motion?
(2002-CE-PHY II - 9)
9.
A block of weight 100 N is placed on a smooth horizontal table. A vertical
force of 60 N and a horizontal force of 30 N are applied to the block as shown.
Find the magnitude of the resultant force acting on the block.
A. 30 N
B. 40 N
C. 50 N
D. 67 N
(2002-CE-PHY II - 10)
10.
The figure above shows a flying wheel in an amusement park. The wheel is of
diameter 18 m and carries eight cages. There is only one passenger of mass 60
kg inside one of the cages. The wheel rotates with uniform speed and it takes
80 s for the passenger to travel from the bottom to the top of the wheel. Find
the average useful power output of the motor of the wheel.
A.
B.
C.
D.
60 10 18 W
 60  10  18 

W
80


 60  10    9 

W
80


60 10    9  80 W
(2002-CE-PHY II - 11)
11.
A block is initially at rest on smooth horizontal ground. Two forces of equal
magnitude F act on the block. In which of the above cases will the block
remain at rest?
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
(2002-CE-PHY II - 12)
12.
Grace and Kitty, of masses 50 kg and 40 kg respectively, stand on light
rollers on a smooth horizontal floor. They are initially at rest with Grace
holding a 2 kg ball. Grace throws the ball to Kitty and moves backward with
a speed 0.8 m s-1 afterwards. After catching the ball, Kitty moves in the
opposite direction as shown above. Which of the following statements is/ are
correct?
(1)
The final speed of Kitty is 0.95m s-1.
(2)
The horizontal momentum of the ball is
conserved in this process.
(3)
The total kinetic energy of Kitty and the ball
decreases when Kitty catches the ball
A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only
(For Questions 1 and 2) The figure shows the velocity-time graph of a car
traveling along a straight road.
(2003-CE-PHY II - 1)
1 What physical quantity does the area of the shaded region represent?
A.
B.
C.
D.
energy
momentum
acceleration
displacement
(2003-CE-PHY II - 2)
2 Which of the following statements are correct?
(1) The car changes its direction of travel at t  t1 .
(2) The car is farthest away from the starting point at t  t1 .
(3) The car returns to its starting point at t  t 2 .
A.
B.
C.
D.
(1) and (2)only
(1) and (3)only
(2) and (3)only
(1), (2) and (3)
(2003-CE-PHY II - 3)
3
A car starts at point A and travels along a circular path of radius 30m. After
15 s, the car returns to point A. Find the average speed of the car within this
period of time.
A.
B.
C.
D.
zero
2 m s-1
6.3 m s-1
12.6 m s-1
(2003-CE-PHY II - 4)
4 A plane starts from rest and accelerates at 2 m s-2. If the minimum take-off
speed is 60ms-1, find the minimum distance traveled by the plane before it
takes off.
A.
B.
C.
D.
450 m
900 m
1800 m
3600 m
(2003-CE-PHY II - 5)
5
A block of mass m slides down an inclined plane with uniform velocity.
What is the net force acting on the block?
A.
B.
C.
D.
mg
mg sin 
mg cos 
zero
6
(2003-CE-PHY II - 6)
The figure shows a ride in an amusement park. A passenger is fastened to a
seat which is then raised to the top of a vertical pole. At time t  0 , the seat
is released from rest and falls freely. After 3 s, the seat is brought to rest at a
point P near the ground. Which of the following graphs best shows the
relation between the gravitational force acting on the passenger W and t ?
7
(2003-CE-PHY II - 7)
A uniform cube of weight 600 N is held in equilibrium in the air by four
identical cables as shown above. If each cable makes an equal angle of 20o
with the vertical, find the tension in each cable.
A.
B.
C.
D.
150 N
160 N
412 N
439 N
(2003-CE-PHY II - 8)
8
Source: Road
Users’ Code,
Transport
Department,
Government of
the HKSAR,
2000
A car accelerates at 3 m s-2 along a straight horizontal road. A child of mass 10
kg is sitting on a safety seat inside the car. Find the magnitude of the resultant
force exerted by the safety seat on the child.
A.
B.
C.
D.
30 N
100 N
104 N
130 N
9
(2003-CE-PHY II - 9)
A wooden block of mass M is hanging freely in the air from a light string of
length l . A bullet, of mass m traveling at a speed v, hits the block and
becomes embedded in it. The block then swings upwards. Which of the
following are employed in determining the maximum height reached by the
block?
(1) law of conservation of energy
(2) law of conservation of momentum
(3) principle of moments
A.
B.
C.
D.
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(2003-CE-PHY II - 10)
10
A uniform rod of weight 50 N is supported by two spring balances P and Q
and remains at rest as shown above. Assume the weight the rod acts through
its mid-point. Find the readings of P and Q.
A.
B.
C.
D.
Reading of P
Reading of Q
17 N
20 N
30 N
33 N
33 N
30 N
20 N
17 N
11 (2003-CE-PHY II - 11)
The photograph shows a man using a spanner to turn a nut. Which of the
following is/are advantage(s) of using the spanner?
(1) The effort required can be reduced.
(2) The efficiency can be increased.
(3) The energy required can be reduced.
A.
B.
C.
D.
(1) only
(2) only
(1) and (3) only
(2) and (3) only
12 (2003-CE-PHY II - 12)
A child is sitting on a chair as shown above. Which of the following pairs of
forces is/are (an) action and reaction pair(s)?
(1) The gravitational
force exerted by the
earth on the child
(2) The force exerted by
the child on the chair
(3) The force exerted by
the chair on the
ground
A.
B.
C.
(1) only
(2) only
(1)and (3) only
D.
(2)and (3) only
The normal
reaction exerted
and
by the chair on
the child
The normal
reaction exerted
and
by the chair on
the child
The gravitational
force exerted by
and
the earth on the
chair