Question

If a ball is thrown with a certain velocity, and it attains a height of 40m and come back the throwen

Answer 1

Distance is not the same as displacement, keep that in mind as you attempt this question .

Take the example of a runner jogging in a square Park of side length say 10m.

After 1 round he ends up covering a distance of 40m in total however his displacement is 0.

Displacement best described in lay man's terms is the shortest path between the starting point of the motion and the ending point of the motion.

So in your question, since the ball comes back to where it was released from, the net displacement is zero.