Question

A CD starts from rest at an angular acceleration of 3 radians/ s2.

(a) Find the angular speed after 10 seconds.

(b) Through what angle does the CD turn in this time of 10 seconds?

Answer 1

(a)

Angular acceleration $(\alpha)$ = 3 / $s^{2}$

Initial angular velocity( $\omega_{0}$ ​​​​​​) = 0

$\omega (t)$ = $\omega_{0}$ + $\alpha$ t

$\omega$ (t=10 sec) = 3 x 10 rad/sec = 30 rad/sec

This angular speed after 10 seconds is 30 rad/sec

(b)

$\theta$ = $\omega_{0}$ t + $\alpha$ $t^{2}$ /2

= 0 +( 3 x 10 x (10/2)) radians ($\omega_{0}$ = 0)

= 150 radians

Thus CD turns by 150 radians