Name: Class: Date:SMK (L) Methodist Kuala Lumpur

STPM Physics Semester 1Post-Test Chapter 5 Circular Motion

SECTION A1. A particle moves with constant speed in a horizontal circle. Which of the following quantities is zero?

A Angular velocity B Angular acceleration

C Centripetal acceleration

D Resultant force

2. For a particle travelling in a horizontal circle with constant angular velocity,A the linear momentum is constant but the energy changes.B the energy is constant but the linear momentum changes.C both the energy and linear momentum are constant.D both the energy and linear momentum change.

3. A pendulum bob is whirled round on a smooth horizontal surface by a string of length l at a constant rate. If the tension in the string is kept constant, which of the following graphs represents the relation between the speed v of the pendulum bob and the length l of the string?

4. A disc rotates horizontally with uniform angular velocity about an axis through its centre. Which of the following graphs shows the correct relationship between the speed v of a point on the disc and the distance r of the point from the centre of the disc?

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5. If the angular velocity of a body performing circular motion is ω, the number of revolutions per second isA zero B C D

6. Two satellites P and Q are in the same circular orbit round the Earth. The mass of P is greater than the mass of Q. Which of the following quantities is NOT greater in the magnitude P than for Q?A Angular velocity B Kinetic energy C Potential energy D Gravitational force

7. An object of mass of 2 kg rotates at constant speed in a horizontal circle of radius 5 m. the time for one complete revolution is 3 s.What is the magnitude of the resultant force acting on the object?.A B C D

8. A body moves in a circle with increasing angular velocity. At times t, the angles Ѳ swept out by the body and its angular velocities ω are as follows:

t/s Ѳ/rad ω/rad s-1

2 14 114 44 196 90 278 152 35

The angular acceleration of the bodyA gradually decreases and is 4.5 rad s-2 when t = 6 s.B is constant at 4 rad s-2

C is constant at 8 rad s-2

D gradually increases and is 4.5 rad s-2 when t = 6 s.

9. The minute hand of a large clock is 3.0 m long. What is its mean angular speed?A B C DE

10. Satellites are in circular orbit around the Earth.What is the relationship between the radii r of their orbits and their speeds v?A B C D

SECTION B1. A string of length, l fixed at one end and a bob of mass, m is attached on another end. A conical

pendulum is formed when the bob moves in a horizontal circle as shown in the diagram below.

Show that the frequency of oscillation, f is given by

where g is the acceleration due to gravity and Ѳ is the angle between the string and the vertical. [5]

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