At t = 0 the current to a dc electric motor is reversed, resulting in an angular displacement of the motor shaft given byθ(t) = (210rad/s)t - (21.5rad/s2)t2 - (1.30 rad/s3)t3.
(a) Find at what time is the angular velocity of the motor shaft zero?
s
(b) Find the angular acceleration at the instant that the motor shaft has zero angular velocity.
rad/s2
(c) Obtain how many revolutions do the motor shaft turn through between the time when the current is reversed and the instant when the angular velocity is zero?
rev
(d) Determine how fast was the motor shaft rotating at t = 0, when the current was reversed?
rad/s
(e) Determine the average angular velocity for the time period from t = 0 to the time calculated in part (a).
rad/s