At t = 0 the current to a dc electric motor is reversed, resulting in an angular displacement of the motor shaft given b

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At t = 0 the current to a dc electric motoris reversed, resulting in an angular displacement of the motorshaft given by 𝜃(t) =(230 rad/s)t − (20.5 rad/s2)t2 − (1.30 rad/s3)t3.
(a) At what time is the angular velocity of the motor shaftzero? s(b) Calculate the angular acceleration at the instant that themotor shaft has zero angular velocity. rad/s2(c) How many revolutions does the motor shaft turn through betweenthe time when the current is reversed and the instant when theangular velocity is zero? rev(d) How fast was the motor shaft rotating at t =0, when the current was reversed? rad/s(e) Calculate the average angular velocity for the time periodfrom t = 0 to the time calculated in part(a). rad/s