A Machinist Turns the Power on to a Grinding Wheel,at

Multiple Choice

A machinist turns the power on to a 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.In this situation,the angular acceleration of the wheel between t = 0 s and t = 10 s is closest to:

A) 3.8 rad/s²
B) 4.6 rad/s²
C) 5.3 rad/s²
D) 6.1 rad/s²
E) 6.8 rad/s²