Rotational Kinematics Part 2

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 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/s²

• 1.6 rad/s²

• 4.3 rad/s²

• 6.2 rad/s²

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

• 4 revolutions

• 2 revolutions

• 3 revolutions

• 5 revolutions

A disc rotating at 300 rev/min is stopped after 2 minutes. Calculate

a) the angular acceleration

b) angular velocity after 30 s

c) the number of revolutions

• a) -0.26 rad s^-2

  b) 23.62 rad s^-1

  c) 302 revolutions

• a) -0.45 rad s^-2

  b) 20.35 rad s^-1

  c) 202 revolutions

• a) -0.62 rad s^-2

  b) 36.22 rad s^-1

  c) 112 revolutions

• a) -0.34 rad s^-2

  b) 13.62 rad s^-1

  c) 422 revolutions