A machinist turns the power upon to grinding wheel, at rest, at time t = 0 s. The wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 38 rad/s. The wheel is run at that angular velocity for 30 s and then power is shut off. The wheel slows down uniformly at 2.1 rad/s2 until the wheel stops. The radius of the wheel is 5 cm. Find the velocity of a point on the perimeter of the wheel during operating velocity.