Explain giving an example that an object can be in motion as well as at rest at the same time.

Rest and Motion are Relative Terms.

An object which is at rest can also be in motion with respect to different refernce points.

eg.) A passenger travelling in a bus; the passenger is at rest with respect to the fellow passengers but it is in motion with respect to the ground

A rock is rest with respect to person in earth

And in motion with respect to a man in other planet as earth rotate sun