An airplane propeller is rotating at 1750 rpm . a)Compute the propeller's angular velocity in rad/s. b)How many seconds does it take for the propeller to turn through 41.0 ∘? c)If the propeller were turning at 21 rad/s , at how many rpm would it be turning? d)When the propeller were turning at 21 rad/s , what is the period (in seconds) of this propeller?