Circular and Rotational Motion MCQs

Question 1

The angular equations of motion are valid only for:

Accepted Answer

constant angular acceleration

Answer

zero angular velocity

Answer

variable angular acceleration

Answer

constant linear speed

Question 2

A bucket of water is swung in a vertical circle of radius 2.5 m. The minimum speed at the top so the water stays in is (g = 9.8 m/s^2):

Accepted Answer

4.95 m/s

Answer

9.9 m/s

Answer

2.47 m/s

Answer

7 m/s

Question 3

Which balance must be kept in a laboratory centrifuge?

Accepted Answer

tubes of equal mass placed opposite each other

Answer

tubes of different masses

Answer

all tubes on one side

Answer

one tube only

Question 4

During the free-fall part of a 'zero-g' aircraft flight, passengers feel weightless because:

Accepted Answer

the aircraft follows a free-fall (parabolic) path

Answer

gravity is switched off

Answer

the engines push them up

Answer

the aircraft leaves the atmosphere

Question 5

A centrifuge tube is 0.1 m from the axis and spins at 3000 rpm. The centripetal acceleration is about how many times g (g = 9.8)?

Accepted Answer

1010 g

Answer

2010 g

Answer

504 g

Answer

3.21 g

Question 6

A 0.2 kg mass rotates at 10 rad/s on a radius of 0.5 m. The centripetal force is:

Accepted Answer

10 N

Answer

5 N

Answer

1 N

Answer

20 N

Question 7

90^circ expressed in radians is:

Accepted Answer

pi2

Answer

pi4

Answer

pi

Answer

2pi

Question 8

An arc of length 6 m on a circle of radius 2 m subtends an angle of:

Accepted Answer

3 rad

Answer

1.5 rad

Answer

172 rad

Answer

6 rad

Question 9

A bathroom scale in an orbiting spacecraft would read:

Accepted Answer

zero

Answer

a negative value

Answer

twice the weight

Answer

the astronaut's normal weight

Question 10

Moment of inertia plays the same role in rotation as:

Accepted Answer

mass plays in linear motion

Answer

energy

Answer

force

Answer

velocity

Question 11

Centripetal force is:

Accepted Answer

not a new kind of force — it is the name for the net inward force

Answer

a force that pushes outward

Answer

always gravitational

Answer

a fictitious force

Question 12

The quantity 'relative centrifugal force (RCF)' compares:

Accepted Answer

romega^2 with g

Answer

speed with time

Answer

density with volume

Answer

mass with weight

Question 13

A wheel starts at 30 rad/s with angular acceleration -3 rad/s^2. In 8 s it turns through:

Accepted Answer

144 rad

Answer

72 rad

Answer

288 rad

Answer

48 rad

Question 14

Torque is maximum when a force is applied:

Accepted Answer

perpendicular to the lever arm, far from the axis

Answer

parallel to the axis

Answer

at the axis

Answer

along the lever arm

Question 15

In orbit, the force of gravity on an astronaut:

Accepted Answer

provides the centripetal force for circular motion

Answer

is balanced by a centrifugal force

Answer

pushes the astronaut outward

Answer

is zero

Question 16

A force of 20 N is applied tangentially at the rim (radius 0.5 m) of a wheel with I = 2 kg m^2. Its angular acceleration is:

Accepted Answer

5 rad/s^2

Answer

2.5 rad/s^2

Answer

10 rad/s^2

Answer

20 rad/s^2

Question 17

A 0.5 kg body moves at 4 m/s in a circle of radius 0.8 m. The centripetal force is:

Accepted Answer

10 N

Answer

2.5 N

Answer

5 N

Answer

20 N

Question 18

A car on a banked road can turn without friction because:

Accepted Answer

the horizontal component of the normal force provides the centripetal force

Answer

its speed is zero

Answer

the road is flat

Answer

gravity pushes it outward

Question 19

270^circ expressed in radians is:

Accepted Answer

3pi2

Answer

2pi3

Answer

3pi4

Answer

3pi

Question 20

Apparent weight is:

Accepted Answer

the contact (normal) force from the floor or scale

Answer

zero on Earth

Answer

the mass of a body

Answer

the gravitational force always

Question 21

A solid disc of mass 10 kg and radius 1 m rotates about its central axis. Its moment of inertia is:

Accepted Answer

5 kg m^2

Answer

4 kg m^2

Answer

2.5 kg m^2

Answer

10 kg m^2

Question 22

For the same mass and radius, which has the larger moment of inertia about its axis?

Accepted Answer

a ring

Answer

a solid disc

Answer

they are equal

Answer

a solid sphere

Question 23

A flywheel (I = 0.8 kg m^2) is brought from rest to 50 rad/s in 10 s. The torque needed is:

Accepted Answer

4 N m

Answer

8 N m

Answer

5 N m

Answer

2 N m

Question 24

If the perpendicular force on a body in circular motion suddenly disappears, the body moves:

Accepted Answer

in a straight line along the tangent

Answer

inward to the centre

Answer

in a smaller circle

Answer

outward along the radius

Question 25

A wheel with moment of inertia 0.5 kg m^2 spins at 20 rad/s. Its angular momentum is:

Accepted Answer

10 kg m^2/s

Answer

200 kg m^2/s

Answer

20 kg m^2/s

Answer

5 kg m^2/s

Circular and Rotational Motion MCQs — Physics (page 5)

101. The angular equations of motion are valid only for:

102. A bucket of water is swung in a vertical circle of radius 2.5 m. The minimum speed at the top so the water stays in is (g = 9.8 m/s^2):

103. Which balance must be kept in a laboratory centrifuge?

104. During the free-fall part of a 'zero-g' aircraft flight, passengers feel weightless because:

105. A centrifuge tube is 0.1 m from the axis and spins at 3000 rpm. The centripetal acceleration is about how many times g (g = 9.8)?

106. A 0.2 kg mass rotates at 10 rad/s on a radius of 0.5 m. The centripetal force is:

107. 90^circ expressed in radians is:

108. An arc of length 6 m on a circle of radius 2 m subtends an angle of:

109. A bathroom scale in an orbiting spacecraft would read:

110. Moment of inertia plays the same role in rotation as:

111. Centripetal force is:

112. The quantity 'relative centrifugal force (RCF)' compares:

113. A wheel starts at 30 rad/s with angular acceleration -3 rad/s^2. In 8 s it turns through:

114. Torque is maximum when a force is applied:

115. In orbit, the force of gravity on an astronaut:

116. A force of 20 N is applied tangentially at the rim (radius 0.5 m) of a wheel with I = 2 kg m^2. Its angular acceleration is:

117. A 0.5 kg body moves at 4 m/s in a circle of radius 0.8 m. The centripetal force is:

118. A car on a banked road can turn without friction because:

119. 270^circ expressed in radians is:

120. Apparent weight is:

121. A solid disc of mass 10 kg and radius 1 m rotates about its central axis. Its moment of inertia is:

122. For the same mass and radius, which has the larger moment of inertia about its axis?

123. A flywheel (I = 0.8 kg m^2) is brought from rest to 50 rad/s in 10 s. The torque needed is:

124. If the perpendicular force on a body in circular motion suddenly disappears, the body moves:

125. A wheel with moment of inertia 0.5 kg m^2 spins at 20 rad/s. Its angular momentum is:

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