A person is riding a bicycle, and its wheels have an angular velocity of +19.5 rad/s. Then, the brakes are applied and the bike is brought to a uniform stop. During braking, the angular displacement of each wheel is +11.5 revolutions.
(a) How much time does it take for the bike to come to rest?
(b) What is the angular acceleration of each wheel?
avg ang. v=ang. x/t
avg ang. a=change in ang. v / t
The Attempt at a Solution
I plugged in and got...
delta theta=11.5 x 2pi=72.26 radians
72.26rad/(t) = 19.5
and so t=3.7 or 3.706 or 3.71 and all those are wrong... I don't know what i did wrong.