Question

a ball hits a wall horizontally at 6m/s. It rebounds horizontally at 4.4m/s.the ball is in contact with the wall for 0.04s.what is acceleration of wall.

Answer 1

The attachment says all, but an alternative could be the concept of relative velocity & relative acceleration.The relative(either velocity or acceleration) of ball(with respect to wall) and of wall(with respect to ball) will be equal and opposite in direction