PDT : Rotational Kinematics

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

• 63.67 rad/s

• 41.9 rad/s

• 3819.71 rad/s

• 2594.31rad/s

A flywheel starts from rest, and has an angular acceleration of 4 rad/s². What will be its angular speed when it has made 2 revolutions?

• 7.09 rad/s

• 6.35 rad/s

• 10.03 rad/s

• 5.01 rad/s

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

• 32 cm/s

• 2 cm/s

• 0.30 cm/s

• 15 cm/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

An object completes 1.5 circular orbits in half a minute. What is its approximate angular velocity?

• 0.052 rad/s

• 0.521 rad/s

• 0.314 rad/s

• 3.14 rad/s

Which of the following is NOT a unit of rotational speed?

• Meters per second

• Revolutions per second

• Revolutions per minute

• Rotations per second

If the translational velocity of an object is 3 m/s, and is located a distance of 2 m from the axis of rotation, what is the object's angular velocity?

• 0.67 rad/s

• 1.5 rad/s

• 5 rad/s

• 6 rad/s

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

A fixed point, around which something turns, perpendicular to the rotation.

• axis of rotation

• diameter

• radius

• circumference of a circle