The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

This discussion is now closed.

Check out other Related discussions

Physics Question on momentum

A ball of mass 0.2kg falls from a height of 45m.On stiking the ground it rebounds in 0.1s with two-thirds of the velocity with which it struck the ground.Calculate
1) the momentum change on hitting teh ground
2)the force on the ball due to the impact
Reply 1
Avatar for Fermat
Fermat
8
Salman
A ball of mass 0.2kg falls from a height of 45m.On stiking the ground it rebounds in 0.1s with two-thirds of the velocity with which it struck the ground.Calculate
1) the momentum change on hitting teh ground
2)the force on the ball due to the impact

1)
ball strikes the ground with velocity = v

v² - u² = 2as
v² = 2gs (initial velocity, u = 0)
v² = 2*9.8*45
v² = 882
v = 29.7 m/s
==========

rebound speed w = (2/3)v
= (2/3)*29.7
= 19.8
but ball is now moving in opposite direction so its velocity is -ve, i.e.
w = -19.8 m/s
==========

Momemtum change is
m(v - w)
= 0.2(29.7 + 19.8)
= 0.2*49.5
= 9.9
=====

2)
Impulse = change in momemtum
Ft = 9.9
F*0.1 = 9.9
F = 99 N
=======

Related discussions

Latest

Trending

Trending

Articles for you