Angular Review

If the body is moving in a circle of radius r with a constant speed v, its angular velocity is

• v² / r

• vr

• v / r

• r / v

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 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 merry go round starts from rest, and reaches an angular speed of 2 radians/second in 3 seconds. What is its angular acceleration, and through what angle does it sweep in the 3 second time interval? 

• α = 3/2 rad/s²,   θ=27/4 rad
• α = 2/3 rad/s², θ=3 rad
• α = 2/3 rad/s², θ=6 rad
• α = 6 rad/s², θ=27 rad

A flywheel starts from rest, and has an angular acceleration of 4 rad/s². What will be its angular speed when it has made one revolution? 

• 5.01 rad/s
• 50.27 rad/s
• 2.83 rad/s
• 7.09 rad/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

An object completes 1.5 circular orbits in half a minute. It orbits with a radius of 2 m. What is the object's tangential speed?

• 0.15 m/s
• 0.60 m/s
• 1.6 m/s
• 6 m/s

A horse gallops around a circular arena.  The centripetal force on the horse is ___.

• directed outward
• tension
• directed toward the center of the arena
• 9.8 N

Which of the following increase the centripetal force?

• Increasing the radius
• Increasing the velocity
• Decreasing the mass
• Decreasing the acceleration