Question

A ball of a mass 1 kg dropped from 20 m height on ground and it rebounds to height 5 m. find magnitude of change in momentum during its collision with the ground considering g=10 m/s

Answer 1

for downward motion ;
u=0 m/s
a=10 m/s2
s=20 m
using v2- u2=2as
v= 20m/s
for upward motion;
v=0 m/s
a=10 m/s2
s=5 m using v2 – u2=2as
u= -10 m/s
I=mv – mu
I=20+10=30 kg m/s