英文物理题A ball of mass 0.100 kg is dropped from rest from a hei

let me try.Since the question is in English,i think i would give the answer in english as well.
use the equation v^2=u^2+2as first
U is the initial velocity,being 0 m/s
a is assumed to be 10 m/s2 ,as it is a free fall situation
S is equal to 1.25 m
Hence we get the value of V,which is the velocity of the ball hiting the ground and rebound.After calculaltion,V = 5
Then use the equation a= (V-U)/t to calculate t.t is the time for the ball to rebound and rise to the highest point.
a= 10m/s2 again as it is still a free fall.
U is now equal to 5 m/s ( cause now we are looking at the rebound process)
V is 0 m/s because at the highest point the ball remain still.
As a result,we find that t = 1/2
Then we calcuate the value of impulse.
The direction is obviously upward.
I = MV
= 0.1 * 5
=0.5 kgm/s
Momentum = MV/t
= 0.5/ (1/2)
= 1
i calculate momentum for your further reference.
Hope i can help you in some way.

一个质量为0.100kg的球由离地面1.25m高度静止状态落下，要使球在地面上反弹后可以达到0.840m高度，地面需要给了球多大的推力（带方向）？
翻译后是这样，题目不会做，很久没碰过物理题了。