Question

An electric motor rotating a workshop grinding wheel at a rate of 95 rev/min is switched off. Assume the wheel has a constant negative angular acceleration of magnitude 2.40 rad/s2.
(a) How long does it take for the grinding wheel to stop?

(b) Through how many radians has the wheel turned during the interval found in (a)?

Answer 1

a. V=95rad/min * 6.28rad/rev * (1/60)min/s = 9.94rad/s.

Vf = Vo - at = 0,
9.94 - 2.4t = 0,
-2.4t = - 9.94,

t = 4.14s.

Answer 2

b. d=9.94rad/s * 4.14s = 41.2 radians.

Answer 3

For part B you have to divide the 9.94 by 2 then multiply by time