Question

In a tumbling clothes dryer, the cylindrical drum (radius 55.0cm and mass 33.0kg ) rotates once every second. a) Determine the rotational kinetic energy about its central axis. b) If it started from rest and reached that speed in 2.90s , determine the average net torque on the dryer drum.

Answer 1

The key formulas here are:
\[I_{cylinder,center}=1/2MR^2\]\[K=1/2I\omega^2\]\[\alpha_{ave}=(\omega_{f}-\omega_{i})/\Delta t\]\[\tau_{ave}=I\alpha_{ave}\]You are given M, R, t, initial angular velocity, and final angular velocity, and can solve for everything else.