Rotational Kinematic Equations

A pulley of radius 0.20 m has a length of string wrapped around it, attached to a mass. The mass is released from rest and falls with an acceleration of 3.0 ms^-2. Find the angular acceleration of the pulley.

• 15 rad/s^2
• 10 rad/s^2
• 5 rad/s^2
• 20 rad/s^2

44 m of cable are pulled off a cable drum with a radius of 0.20 m. It takes 22 s to unwind the cable at a steady speed. Through how many revolutions does the drum turn?

• 25.67
• 39.82
• 42.15
• 34.91

A centrifuge used to separate the components of blood can rotate at 85 revolutions per second. The centrifuge takes 120 seconds to reach top speed from rest. Calculate the angular acceleration.

• 0.85 rad/s^2
• 4.40 rad/s^2

• 1.25 rad/s^2
• 3.75 rad/s^2

A large grinding wheel accelerates from rest with an angular acceleration of 0.50 rad s^-2. Find the time taken for the grinding wheel to reach an angular velocity of 25 rad s^-1

• 75 s
• 50 s
• 40 s
• 10 s

When switched off, the blades of an electric fan take 12 s to slow down and stop. During this time they complete 20 revolutions. What was the initial angular velocity of the fan?

• 21 rad/s

• 14 rad/s

• 35 rad/s

• 27 rad/s

Which of the following greek symbols is used to represent angular acceleration?

• β
• γ
• δ
• α

Which of the definitions below can best describe angular velocity?

• Distance traveled by a rotating object
• Speed of rotation of an object
• Rate of change of angular displacement with respect to time
• Rate of change of linear displacement with respect to time

A bike wheel rotates 15 times, what is its angular displacement? (measured in radians)

• 94.2

• 180.2
• 120.5
• 57.4