give an example to show that displacement can be negative?
Displacement is vector quantity which has magnitude as well as direction. Therefore, the negative displacement can be easily shown using a proper frame of reference. Suppose a motion starts from a point A. Here point A is our origin. Let us assume moving to right be a positive direction. This is our frame of reference.
Let a body starts to move from point A to point B 20m right and then B to C 30m left. Then, here A to C we have negative displacement of 10m.
Hope this helps,