Rotational Kinematics

Which has greater angular speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?

• The inside horse

• The outside horse

• Neither - they both have the same angular speed

A fan spins with a constant angular speed of 500 radians/second. How long will it take to cover an angle of 2π radians (one revolution)?

• 0.013 s
• 0.002 s
• 76.9 s
• 6.28 s

A gear spins at a rate of 400 revolutions/minute. Which choice is closest to its angular speed in radians/second?

• 6.67 rad/s

• 2500 rad/s

• 41.9 rad/s

• 20.9 rad/s

Two bugs ride a turntable which is rotating at a constant rate of 4 rad/s. Bug B is at a radius of 4 cm, while bug A is at a radius of 8 cm. Which of the following is true?

• Bug A has a greater rotational speed.

• Bug B has a greater rotational speed.

• Bug B has a greater speed.

• Bug A has a greater speed.

An object moves in a circle at a constant speed. Which of the following is NOT true f the object?

• its centripetal acceleration points toward the center of the circle

• its tangential speed is constant

• its velocity is constant

• a centripetal force acts on the object

A fan blade, initially at rest, rotates with a constant acceleration of 0.025 rad/s². What is the time interval required for it to reach a 4.2 rad displacement after starting from rest

• 1.8 s

• 2.0 s

• 16 s

• 18 s

A 0.12-m-radius grinding wheel takes 5.5 s to speed up from 2.0 rad/s to 11.0 rad/s. What is the wheel's average angular acceleration?

• 9.6 rad/s/s

• 4.8 rad/s/s

• 3.1 rad/s/s

• 1.6 rad/s/s

A 0.30m radius automobile tire rotates how many rad after starting from rest and accelerating at a constant 2.0 rad/s² over a 5.0 s interval?

• 125 rad

• 25 rad

• 2 rad

• 0.5 rad

As a young boy swings a yo-yo parallel to the ground and above his head, the yo-yo has a centripetal acceleration of 250 m/s^2. If the yo-yo’s string is 0.50 m long,what is the yo-yo’s tangential speed?

• 11 m/s

• 15 m/s

• 112 m/s

• 22 m/s

In order to do a lot of flips an Olympic diver would want:

• A high rotational inertia

• A low rotational inertia

• A low linear acceleration

• A low angular velocity