The spin-drier of a washing machine slows down uniformly from 700 rpm (revolutions per minute) to 140 rpm while making 50 revolutions. Find the angular acceleration through these 50 revolutions. Express your answer in rad/s^2.

Question

The spin-drier of a washing machine slows down uniformly from 700 rpm (revolutions per minute) to 140 rpm while making  50 revolutions.  Find the angular acceleration through these 50 revolutions.  Express your answer in rad/s^2.

Henry · Answer

(140-700) = -560 rev/min -560rev/min * 1min/60s * 6.28rad/rev = -58.6 rad/s. = The change in velocity. 60s/560rev * 50rev = 5.36 s. a = (-58.6)/5.36 = -10.9 rad/s^2.