Question Detail
Question
If the net torque acting on a rotating object is zero, which quantity must remain constant?
Correct Answer
Option D is the correct answer.
Detailed Explanation
The relationship τ = dL/dt (where L is angular momentum) implies that if the net external torque τ is zero, then dL/dt = 0, meaning angular momentum L is constant. This is the law of conservation of angular momentum.
Hint
Torque is the rate of change of angular momentum. If the rate of change is zero, the quantity itself is constant.