An automatic dryer spins wet clothes at an angular speed of 5.2 rad/s. Starting from rest, the dryer reaches its operating speed with an average angular acceleration of 3.2 rad/s². How long does it take the dryer to come up to speed?

Time taken by dryer to come up to speed is 1.625 seconds.

Explanation:

We have equation of motion v = u + at

Initial velocity, u = 0 rad/s

Final velocity, v = 5.2 rad/s

Time, t = ?

Acceleration, a = 3.2 rad/s²

Substituting

v = u + at

5.2 = 0 + 3.2 x t

t = 1.625 s

Time taken by dryer to come up to speed is 1.625 seconds.