Question

The vertical walls separated by a distance 200m. A ball is projected horizontally with an speed 100m, from one wall to another. Height of projection is
50m from ground. All collisions between wall and ball are elastic. Takeg = 10m/s2
Q. Displacement of the ball,
(A) 10
(B) 10, 19
(C) 10/29
(D) None of these

Answer 1

If the kinetic energy is the same, then the collision is elastic. If the kinetic energy changes, then the collision is inelastic regardless of whether the objects stick together or not. In either case, for collisions with no external forces, momentum is conserved.