## Car and Truck in Head-on Collision

### Inelastic Collision

This animation depicts an inelastic collision between a truck and
a car. In the collision between the truck and the car, total system
momentum is conserved. Before the collision, the momentum of the car
is 20000 kg*m/s and the momentum of the truck is 0 kg*m/s. The total
system momentum is 20000 kg*m/s. After the collision, the momentum of
the car is 5000 kg*m/s and the momentum of the truck is 15000 kg*m/s.
The total system momentum is 20000 kg*m/s. Consistent with the law of
conservation of momentum, the total system momentum is conserved. The
momentum lost by the car (15000 kg*m/s) is gained by the truck.

An analysis of the kinetic energy of the two vehicles reveals that
the total system kinetic energy before the collision is 200000 Joules
(200000 J for the car plus 0 J for the truck). After the collision,
the total system kinetic energy is 50000 Joules (12500 J for the car
and 37500 J for the truck). The total kinetic energy before the
collision is not equal to the total kinetic energy after the
collision. A portion of the kinetic energy is converted to other
forms of energy such as sound energy and thermal energy. A collision
in which total system kinetic energy is not conserved is known as an
inelastic collision.

For more information on energy concepts and principles, visit
The Physics Classroom.
Detailed information is available there on the following topics:

Momentum
Momentum
Conservation Principle

Isolated
Systems

Momentum
Conservation in Collisions

Kinetic
Energy

Other animations can be seen at the Multimedia
Physics Studios.

© Tom Henderson, 1996-2007

All Rights Reserved.