Question

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?

Answer 1

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.