Question

when displacement is equal to zero??

Answer 1

when there is no movement....
hope it will help you if it is right then mark as brainalist first

Answer 2

when we throw a ball up in the air, for whole of the journey covered by the ball, displacement would be zero as the ball comes back to its original position in the final situation and hence the starting point and end point remains the same which means, shortest distance between terminal points=0 and hence displacement=0.