plz answer my 14 question in (attached image) plz answer my question as soon as possible

The initial momentum along P is m.v.Sin in the downward direction. After collision the momentum still remains the same. Thus the change in momentum along P is 0. However when the change in momentum perpendicular to P is taken, initial momentum is m.v.Cos into the wall and final momentum is the same in a direction out of the wall. So the change in momentum is 2mvCos. All the calculations are done assuming there is no gravity.