Question

An electic fan rotating at 3 rev/s-1 is switched off.it comes to rest in 18 sec,the deceleration produced is?

Answer 1

We have,

Initial angular velocity, $\omega_o$ = 3 rev/s

Final angular velocity, $\omega$ = 0

Time t = 18 sec

Using first equation of circular motion,

$\omega = \omega_o + \alpha t$

$0 = 3 + \alpha\times 18$

$\alpha = -0.166 rev/s^2$