Show that the displacement can be zero even if the body has covered a certain distance

Yes displacement can be even the body covers some distance.

Explanation:

If a body moves in a closed path. i.e.

Circular path.

If a body starts moving fom point A and comes back to the same point A the displacement will be. Becuase displacemabt is the shortest possible distance between the starting and ending point.

grav force prop 1/r squared 2r all squared is 4rsquared 1/4rsquared quartered