Question

A body of mass 5 kg is ejected vertically to a height of 7.2 m from the ground when a force acts on it for 0.1s. Calculate the force used to eject the body.

Answer 1

v² = u² - 2gs
0= u² - 2 x 10 x 7.2
u= 12m/s
v=0
Ft = momentum
F= 5 x 12/0.1
=600N