A disk of moment of inertia 80 kg.m² is free to rotate about its axis (through the center, perpendicular to the plane of the disk, which is set vertical). To increase its angular velocity uniformly from rest to 5.0 rad/s in 20.0 s, the work done by the applied torque is A) 1.0 * 10³ J. B) 4.0 F*10² J. C) 2.0 * 10² J. D) 3.2 J. E) 1.6 J.

Question

Quizplus · Accepted Answer

The work done by the applied torque is equal to the change in kinetic energy. The final kinetic energy is (1/2) * I * ω^2 = (1/2) * 80 * (5)^2 = 1000 J.

A Disk of Moment of Inertia 80 Kg