Dr Gulshan S. answered 10/17/20
Physics Teaching is my EXPERTISE with assured improvement
As the brakes are applied to a bicycle wheel, the angular velocity of the wheel changes from 64 rad s-1 to 42 rad s-1.If the wheel turns through exactly 13 revolutions whilst the brakes are being applied.
Find the angular acceleration
w0= 64rad/s
wf = 42 rad/s
Number of revolution = 13 Each revolution = 2 pi
Angle = 13*2pi radian = 26 pi
use wf2 = w02 +2 ( Angular Acceleration ) Angle covered
so 42 *42 = 64*64 + (2 α) *26 *∏
Get α from here
It will be negative means Deacceleration ( Plug in ∏ = 3.14 )