Question

An automatic dryer spins wet clothes at an angular speed of 4.3 rad/s. Starting from rest, the dryer reaches its operating speed with an average angular acceleration of 4.0 rad/s2. How long does it take the dryer to come up to speed

Answer 1

The time taken by dryer to come up to speed is 1.075 seconds.

Step-by-step explanation:

Initial angular speed,
`\omega_i=0`

Final angular speed,
`\omega_f=4.3\ rad/s`

The dryer reaches its operating speed with an average angular acceleration of,
`a=4\ rad/s^2`

Let t is the time taken by dryer to come up to speed. Using first equation of motion as :

`\omega_f=\omega_i+\alpha t\\\\t=(\omega_f)/(\alpha )\\\\t=(4.3)/(4)\\\\t=1.075\ s`

So, the time taken by dryer to come up to speed is 1.075 seconds.