a person riding a bicycle whose wheels have an angular velocity of 20 rad/s. The brakes are applied, and the bike is brought to a stop through a uniform acceleration. During braking, the angular displacement of each wheel is 15.92 revolutions. How long does it take for the bike to come to a stop?

Question

a person riding a bicycle whose wheels have an angular velocity of 20 rad/s. The brakes are applied, and the bike is brought to a stop through a uniform acceleration. During braking, the angular displacement of each wheel is 15.92 revolutions. How long does it take for the bike to come to a stop? 
For this question I got 5 seconds but my teacher said it was ten seconds. I do not think I am doing anything wrong. Could someone tell me if I am wrong or right?

Damon · Answer

during the stop, which starts at 20 and ends at 0, the average angular velocity is 10 rad/s

1 rev = 2pi rad
15.92 revs = 2*pi*15.92 rad

so
2 pi * 15.92 rad/10 rad/s = about 10 s, yes I agree with teacher

Zoey · Answer

Would I use this equation: w=deltaOMEGA/deltaTIME