A machinist turns the power on to a grinding wheel, at rest, t=0. The wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 42 rad/s. The wheel is run at that velocity for 39s and then the power is shut off. The wheel decelerates uniformly at 2.6 rad/s^2 until it stops. What is the angular acceleration of the wheel between t=0 and t=10?

A. 7.6
B. 4.2
C. 5.9
D. 5.0
E. 6.7
:confused:

Use v = u + at

The other pieces of data are not necessary, but are more sort of misleading.

v is the final velocity
u the initial velocity
a the acceleration
t the time.

I hope it helped! :)