Circular and Rotational Motion MCQs

Question 1

A point is 0.5 m from the axis of a wheel rotating at 10 rad/s. Its centripetal acceleration is:

Accepted Answer

50 m/s^2

Answer

5 m/s^2

Answer

100 m/s^2

Answer

25 m/s^2

Question 2

If a star collapses to a smaller radius, its rate of spin:

Accepted Answer

increases greatly

Answer

stops

Answer

decreases

Answer

stays the same

Question 3

A perpendicular (deflecting) force of constant magnitude on a body moving at constant speed produces:

Accepted Answer

uniform circular motion

Answer

simple harmonic motion

Answer

a straight line

Answer

a parabola

Question 4

A conical pendulum's centripetal force is provided by:

Accepted Answer

the horizontal component of the string tension

Answer

gravity alone

Answer

the vertical component of tension

Answer

air drag

Question 5

Which statement about a geostationary satellite's crew (if any) is true?

Accepted Answer

They would feel weightless, though gravity acts on them

Answer

There is no gravity at that height

Answer

They would be pressed to the floor

Answer

They feel their full Earth weight

Question 6

Moment of inertia depends on:

Accepted Answer

the mass and how it is distributed about the axis

Answer

the angular velocity

Answer

the mass only

Answer

the torque applied

Question 7

A cat twisting in mid-air to land on its feet uses:

Accepted Answer

conservation of angular momentum (rotating parts in opposite senses)

Answer

air resistance only

Answer

conservation of linear momentum only

Answer

gravity's torque

Question 8

An arc of length 10 m on a circle of radius 4 m subtends an angle of:

Accepted Answer

2.5 rad

Answer

5 rad

Answer

143 rad

Answer

1.25 rad

Question 9

A wheel starts at 10 rad/s with angular acceleration 2 rad/s^2. In 6 s it turns through:

Accepted Answer

96 rad

Answer

132 rad

Answer

48 rad

Answer

192 rad

Question 10

360^circ expressed in radians is:

Accepted Answer

2pi

Answer

pi

Answer

4pi

Answer

pi2

Question 11

If a body moves in a circle at constant speed, its kinetic energy:

Accepted Answer

stays constant

Answer

decreases

Answer

becomes zero

Answer

increases

Question 12

A 70 kg body moves at 10 m/s in a circle of radius 20 m. The centripetal force is:

Accepted Answer

350 N

Answer

175 N

Answer

700 N

Answer

35 N

Question 13

A torque of 4 N m acts on a wheel with I = 0.5 kg m^2. Its angular acceleration is:

Accepted Answer

8 rad/s^2

Answer

16 rad/s^2

Answer

2 rad/s^2

Answer

4 rad/s^2

Question 14

One radian is approximately:

Accepted Answer

57.3^circ

Answer

1^circ

Answer

180^circ

Answer

3.14^circ

Question 15

The angle between the velocity and the centripetal acceleration in uniform circular motion is:

Accepted Answer

90^circ

Answer

0^circ

Answer

180^circ

Answer

45^circ

Question 16

Astronauts in an orbiting satellite feel weightless because:

Accepted Answer

they and the satellite are in free fall together

Answer

the satellite is outside the Earth's gravity

Answer

they have no mass

Answer

there is no gravity in space

Question 17

A body completes one revolution every 2 s. Its angular velocity is:

Accepted Answer

3.14 rad/s

Answer

0.5 rad/s

Answer

1.57 rad/s

Answer

6.28 rad/s

Question 18

A wheel starts at 5 rad/s with angular acceleration 0.5 rad/s^2. In 20 s it turns through:

Accepted Answer

200 rad

Answer

100 rad

Answer

300 rad

Answer

400 rad

Question 19

A solid disc of mass 4 kg and radius 0.3 m rotates about its central axis. Its moment of inertia is:

Accepted Answer

0.18 kg m^2

Answer

0.144 kg m^2

Answer

0.36 kg m^2

Answer

0.09 kg m^2

Question 20

The angular momentum of a particle of mass m moving at speed v in a circle of radius r is:

Accepted Answer

mvr

Answer

mr^2

Answer

mv^2/r

Answer

12mv^2

Question 21

A person on a freely rotating stool holds weights at arm's length and then brings them in. The rotation:

Accepted Answer

speeds up

Answer

slows down

Answer

reverses

Answer

stops

Question 22

Three masses of 1 kg each are at 1 m, 2 m and 3 m from an axis. Their moment of inertia about the axis is:

Accepted Answer

14 kg m^2

Answer

36 kg m^2

Answer

6 kg m^2

Answer

12 kg m^2

Question 23

When the skater pulls in her arms, her rotational kinetic energy:

Accepted Answer

increases (she does work pulling her arms in)

Answer

becomes zero

Answer

decreases

Answer

stays the same

Question 24

A car turns a corner at steady speed. The horizontal force that makes it turn is:

Accepted Answer

friction between the tyres and the road, towards the centre

Answer

an outward centrifugal force

Answer

the engine force forward

Answer

air resistance

Question 25

Artificial gravity in a space station is produced by:

Accepted Answer

rotating the station so the floor pushes astronauts towards the centre

Answer

switching on a gravity machine

Answer

adding heavy weights

Answer

using magnets

Circular and Rotational Motion MCQs — Physics (page 6)

126. A point is 0.5 m from the axis of a wheel rotating at 10 rad/s. Its centripetal acceleration is:

127. If a star collapses to a smaller radius, its rate of spin:

128. A perpendicular (deflecting) force of constant magnitude on a body moving at constant speed produces:

129. A conical pendulum's centripetal force is provided by:

130. Which statement about a geostationary satellite's crew (if any) is true?

131. Moment of inertia depends on:

132. A cat twisting in mid-air to land on its feet uses:

133. An arc of length 10 m on a circle of radius 4 m subtends an angle of:

134. A wheel starts at 10 rad/s with angular acceleration 2 rad/s^2. In 6 s it turns through:

135. 360^circ expressed in radians is:

136. If a body moves in a circle at constant speed, its kinetic energy:

137. A 70 kg body moves at 10 m/s in a circle of radius 20 m. The centripetal force is:

138. A torque of 4 N m acts on a wheel with I = 0.5 kg m^2. Its angular acceleration is:

139. One radian is approximately:

140. The angle between the velocity and the centripetal acceleration in uniform circular motion is:

141. Astronauts in an orbiting satellite feel weightless because:

142. A body completes one revolution every 2 s. Its angular velocity is:

143. A wheel starts at 5 rad/s with angular acceleration 0.5 rad/s^2. In 20 s it turns through:

144. A solid disc of mass 4 kg and radius 0.3 m rotates about its central axis. Its moment of inertia is:

145. The angular momentum of a particle of mass m moving at speed v in a circle of radius r is:

146. A person on a freely rotating stool holds weights at arm's length and then brings them in. The rotation:

147. Three masses of 1 kg each are at 1 m, 2 m and 3 m from an axis. Their moment of inertia about the axis is:

148. When the skater pulls in her arms, her rotational kinetic energy:

149. A car turns a corner at steady speed. The horizontal force that makes it turn is:

150. Artificial gravity in a space station is produced by:

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