If a wheel revolving at 1800 r.p.m. slows down uniformly to 1200 r.p.m. in 25s, calculate the angular acceleration of the wheel and the number of revolutions it makes in this time.

Answer 1

1800 rev/min * 2 pi rad/rev * 1 min/60 s = Omegai
1200 similarly ---> Omegaf

d omega = (Omegaf-omegai)
dt = 25 s

so
d Omega/dt = alpha = d omega/dt

average angular velocity
= (Omagaf+Omegai)/2
total radians = average vel * 25 sec

total revs = total radians/2pi