If there is a net torque on a wheel, then
A) there must be a net force on the wheel.
B) the wheel must have a nonzero angular acceleration.
C) the wheel cannot be spinning.
D) the angular momentum of the wheel cannot change direction.

Question

Quizplus · Accepted Answer

Net torque causes angular acceleration according to the equation τ = Iα, where τ is the torque, I is the moment of inertia, and α is the angular acceleration. Therefore, if there is a net torque on a wheel, there must be a nonzero angular acceleration. Option A is not necessarily true because a net torque can occur without a net force (e.g. when two equal and opposite forces act on different points of the wheel). Option C is not true because a wheel can spin while experiencing a net torque. Option D is not necessarily true because the direction of angular momentum can change if there is a net torque.

If There Is a Net Torque on a Wheel, Then