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SKHLMC by S.B. WONG
Physics AL / ASL Past - Examinations Questions (Circular Motion)
1982-I-5
A stone of weight w tied to a piece of string is swing in a vertical circle. At the topmost point of its
path, the tension in the string is T and the centripetal force is F. Which of the following statements
is true ?
A. F = w + T
B. F = w  T
C. The net force acting downwards on the stone is F + T + w
D. The net force acting downwards on the stone is F  T + w
E. The net force acting downwards on the stone is F  T  w
1983-I-3
A boy is whirling a stone, tied to a piece of string, in a vertical circle as shown above. The string
suddenly breaks at P. Which of the paths (I - V) represents a possible path for the stone from just
before the string breaks until the stone hits the ground ?
A. I
B. II
C. III
D. IV
E.
V
1985I3
A motorcyclist going round a corner on a level road leans over at an angle to the horizontal. The
reason for this is
A.
to allow his weight to exert a torque about the contact point on the ground.
B.
to increase the frictional force between the motorcycle and the road.
C.
to lower his centre of mass.
D.
to provide the centripetal force.
E.
to reduce the radius of curvature of his path.
1986I5.
A particle P is placed at a height h on a smooth loop-the loop track, as shown. the radius of the loop
is r. P is now released from rest. If P is to complete the loop, the minimum value of h should be
A. 2 r.
B. 2.5 r.
C. 3 r.
D. 4 r.
E.
5 r.
1988I6
A car of mass m travels into a region where the track is an arc of a vertical circle of radius r. At the
bottom of this arc, the car travels at speed v. At this position the vertical force exerted upwards by
the track on the car is
A. mv2/r.
B. mg.
C. mv2/r - mg.
D. mg - mv2/r.
E. mg +
2
mv /r.
1989I8
Section A : Mechanics (3. Circular Motion  M.C.)
P.1
SKHLMC by S.B. WONG
Physics AL / ASL Past - Examinations Questions (Circular Motion)
A smooth conical container rotates about the axis AB as shown. A marble remains at rest relative to
the container at a radial distance r from the axis. If the velocity of the marble is v, then v2 is equal to
A. gr sin 30.
B. gr tan 30.
C. gr/tan 30. D. gr cos 30.
E.
gr/cos 30.
1989I11
Assuming the Earth to be a perfect sphere, what would its angular velocity of rotation have to be for
an object at the equator to be weightless (i.e. to give a spring balance reading of zero) ?
( Radius of the earth = 6.4  106 m. )
A. 2.4  10-12 rad s -1
B. 1.6  10-6 rad s -1
C. 1.3  10-3 rad s -1
D. 8.0  102 rad s -1
E.
6.4  105 rad s -1
1990I6
A spring of unstretched length 10.0 cm, has one fixed to the ceiling. A mass is suspended at the
other end, and the extension so produced is 3.0 cm. When the mass is set to rotate in a horizontal
circular path the length of the spring is 16.0 cm. The angle between the spring and the vertical is .
A. 15.
B. 30.
C. 45.
D. 60.
E.
75
1991I6
The diagram shows part of the route of a rooler-coaster in an amusement park. The cart descends
from H, completes a circular loop A and moves to B. If the cart of passengers is to complete the
central circular track safely, what is the minimum velocity of the cart at the bottom of the circular
track A ? (Assume that there is no friction between the cart and the track.)
A. 10 ms-1
B. 20 ms-1
C. 22.4 ms-1
D. 24.5 ms-1 E. 30 ms-1
1993I8
The figure shows a small heavy bob P attached to a fixed point A on the ceiling by a light
inextensible string. The bob is pulled aside with the string taut and then released from rest. Which
of the following descriptions is/are true ?
(1) When moving towards the lowest point of its path, the angular speed of the bob is increasing.
(2) The centripetal acceleration of the bob is constant.
(3) When the bob is at the lowest point, the tension in the string equals the centripetal force.
A. (1) only
B. (3) only C. (1) and (2) only D. (2) and (3) only E.
(1), (2) and (3)
1994I5(AL)/7(AS)
Section A : Mechanics (3. Circular Motion  M.C.)
P.2
SKHLMC by S.B. WONG
Physics AL / ASL Past - Examinations Questions (Circular Motion)
A student whirls a small bucket of water in a vertical circle of radius 0.6 m. For no spilling, what is
the minimum speed of the bucket at the highest point of its path ?
A. 2.45 ms-1 B. 3.46 ms-1
C. 4.08 ms-1 D. 4.90 ms-1
E. 5.77 ms-1
1995I5(AL)/4(AS)
A small object of mass 0.05 kg is released from rest at the aim of a heavy smooth semi-spherical
bowl of radius 10 cm. Find the force acting on the object by the bowl when it passes the bottom of
the bowl.
A. 0.5 N
B. 1.0 N
C. 1.5 N
D. 2.0 N
E.
2.5 N
1995I6AL)
An aircraft flies along a horizontal circle of radius 10 km with a constant speed of 155 m s -1.
Calculate the angle between its wings and the horizontal.
A. 11.5o
B. 12.0o
C. 12.5o
D. 13.0o
E.
13.5o
1996IIA7(AL)
A small object P of mass 0.3 kg is attached to one end of a light, rigid rod of length 0.5 m, which is
free to rotate about the other end O as shown. The object is swung to rotate in a vertical circle so
that it attains a speed of 2 m s1 at its topmost position. What is the force exerted on one end of the
rod at this instant ?
A. a compressive force of 0.6 N
B. a tensional force of 0.6 N
C. a tensional force of 2.4 N
D. a tensional force of 5.4 N
E. a compressive force of 5.4 N
1997IIA4(AL)/(AS)
The figure shows a car moving round a corner with a radius of 8 m on a banked road of inclination
20 . At what speed would there be no friction acting on the car along OA ?
A. 5.0 m s1
B. 5.2 m s1 C. 5.4 m s1 D. 5.6 m s1
E.
5.8 m s1
1997IIA5(AL)/(AS)
A ball bearing is released from rest at a height h on a smooth track and completes the circular loop
of the track. If R is the reaction acting on the ball bearing at the highest point A of the loop, which
of the following graphs correctly shows the variation of R with h ?
Section A : Mechanics (3. Circular Motion  M.C.)
P.3
SKHLMC by S.B. WONG
Physics AL / ASL Past - Examinations Questions (Circular Motion)
E
2000IIA5(AL)
C
2000IIA8(AL)
A
Section A : Mechanics (3. Circular Motion  M.C.)
P.4