Which is an example of the force of gravity of the earth

GP Motion Force

Which one of the following is an example of the force of gravity of the earth acting on a vibrating pendulum bob?

  1. Applied force
  2. Frictional force
  3. Restoring force
  4. Virtual force

Answer

Every SHM (Simple Harmonic Motion) needs a restoring force. In case of pendulum restoring force is:

 

The correct option is C.