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

Answer:

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

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 :

$\omega_f=\omega_i+\alpha t\\\\t=\dfrac{\omega_f}{\alpha }\\\\t=\dfrac{4.3}{4}\\\\t=1.075\ s$

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