Chapter 5 Momentum
Ewen et al. 2005)
Objective:
•Apply the law of conservation of momentum to both
elastic and inelastic collisions of two objects.

Whenever two objects collide in the absence
of external forces, the total momentum of
the objects before the collision equals to the
momentum after the collision.
 pbeforecollision   pafter collision

When two objects collide and return to their
original shape without being permanently
deformed.

When two objects collide and couple
together.

Elastic Collision
m1v1  m2v2  m v  m v
'
1 1

'
2 2
Inelastic Collision
m1v1  m2v2  m1  m2 v
'

One ball of mass 0.600 kg traveling 9.00 m/s
to the tight collides with a second ball of
mass 0.300 kg traveling to the left. After the
collision, the heavier ball is traveling 2.33 m/s
to the left. What is the velocity of the lighter
ball after the collision?

A 1.75 E4 kg railroad car traveling 8.00 m/s to
the east collides and couples with a stopped
2.25 E4 kg railroad car. What is the velocity of
the joined railroad cars after the collision?