Question

Give an example in which the net force acting on an object is zero and yet the net torque is nonzero.

Answer 1

An example is the case shown in the figure.

Two forces F₁ and F₂ act on a rigid rod that can rotate around a fixed point O. These forces are the same in magnitude and directed in opposite directions.

Thus, the net force acting on the rod is zero. But the net torque is nonzero, beacose these two forces act on different points of the rod.