Find the angular velocity of a body rotating with an acceleration of 2 rev/s square as it completes the 5th revolution after the start.

Answer 1

I assume they want the angular velocity in radians/sec units.

After 5 revolutions, the angle turned is
A = 10 pi radians
The angular acceleration rate is
alpha = 4 pi radians/s^2
The time since starting is given by
A = (1/2)*alpha*t^2
t^2 = 2A/alpha = 5 sec^2
t = 2.236 s
w(at t = 2.236 s) = alpha*t = 28.1 rad/s