[المتفيزق]

At t = 0, a wheel rotating about a fixed axis at a constant angular acceleration has an angular velocity of 2.0 rad/s. Two seconds later it has turned through 5.0 complete revolutions. What is the angular acceleration of this wheel?
a. 17 rad/s2 b. 14 rad/s2 c. 20 rad/s2 d. 23 rad/s2 e. 13 rad/s2

ok...
here we have:
wo = 2 rad/s theta= 5 *2*pi t =2s so:
theta = wo*t +0.5*alpha *t2
10*pi= 2*2+0.5*alpha*4 ... this implies:
31.4 - 4 = 2*alpha
or alpha= 13.7 rad/s2 which is nearly 14rad/s2
thanks