1 A particle \(P\) is projected vertically downwards with initial speed \(3.5 \mathrm {~ms} ^ { - 1 }\) from a point \(A\) which is 5 m above horizontal ground.
- Find the speed of \(P\) immediately before it strikes the ground.
After striking the ground, \(P\) rebounds and moves vertically upwards and 0.87 s after leaving the ground \(P\) passes through \(A\).
- Calculate the speed of \(P\) immediately after it leaves the ground.
It is given that the mass of \(P\) is 0.2 kg .
- Calculate the change in the momentum of \(P\) as a result of its collision with the ground.