## Truck Rear Ends Car

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
truck is 60 000 kg*m/s and the momentum of the car is 0 kg*m/s. The
total system momentum is 60 000 kg*m/s. After the collision, the
momentum of the truck is 45 000 kg*m/s and the momentum of the car is
15 000 kg*m/s. The total system momentum is 60 000 kg*m/s. Consistent
with the law of momentum conservation, the total system momentum is
conserved. The momentum lost by the truck (15 000 kg*m/s) is gained
by the car.

An analysis of the kinetic energy of the two vehicles reveals that
the total system kinetic energy before the collision is 600 000
Joules (600 000 J for the truck plus 0 J for the car). After the
collision, the total system kinetic energy is 450 000 Joules (337 500
J for the truck and 112 500 J for the car). 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

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