A 0.18 m radius pulley is free to rotate about a horizontal axis.A 4.2 kg mass and a 8.0 kg mass are attached by a massless string,which is hung over the pulley.If the string does not slip,calculate the magnitude of the net torque on the pulley about its rotational axis.
A)6.7 N ∙ m
B)5.5 N ∙ m
C)7.6 N ∙ m
D)9.5 N ∙ m

Question

Quizplus · Accepted Answer

The net torque is calculated using the difference in gravitational forces acting on the two masses, multiplied by the radius of the pulley: (8.0 kg - 4.2 kg) * 9.8 m/s² * 0.18 m = 6.7 N ∙ m.

A 018 M Radius Pulley Is Free to Rotate About a a Horizontal