A 1.11 kg toy train rolls around a circular horizontal track. If the train has an angular acceleration of -2.2 rads/s2 and is released with an angular speed of 17.0 rpm, what time is required for the train to come to a complete stop?

Answer 1

Vo = 17rev/min. * 6.28rad/rev * 1min/60s = 1.78 rad/s.

V = Vo + a*t.
0 = 1.78 - 2.2*t, t = ?.