Question

The drill bit of a variable speed electric drill has a constant angular acceleration of 2.50 rad/s^2. the initial angular speed of the bit is 5.00 rad/s. after 4.00s, (a) what angle has the bit turned through and (b) what is the bit's angular speed?

Answer 1

(a) just as with linear motion, 5t + 1/2 at^2
(b) since the speed increases by 2.5rad/s every second, it will have increased by 10 rad/s after 4 seconds.

Answer 2

a. 15rad/s * 4s = rad.
b. V = Vo + a*t = 5 + 2.5*4 = rad/s.