Final answer:
The restoring force in a ball and bowl system in simple harmonic motion (SHM) is never zero.
Step-by-step explanation:
In a ball and bowl system, the restoring force is the force that brings the ball back to its equilibrium position when it is displaced. In a simple harmonic motion (SHM), the restoring force is proportional to the displacement from the equilibrium position. It is important to note that the restoring force is never zero in a ball and bowl system because there is always some displacement from the equilibrium position.