### COLLISION

COLLISION:
Redistribution of momentum of particles happend is said to be collision.

ELASTIC COLLISION:
In a collision, linear momentum and kinetic energy both are conserved then such collision is said to be elastic collision.
Eg: Collision between fundamental particles.
Inelastic Collision:
In a collision, linear momentum conserved but kinetic energy is not conserved then such collision is said to be elastic collision.
Eg: Collision between heavy massive particles.

Coefficient of restitution:   It is defined as the ration between relative velocity of separation after collision to the relative velocity of collision before collision.

( v2 - v1)
e  =       --------------------
(u1 - u2)
Line of Impact:
At the time of collision between two bodies there is a contact during collision. If a line drawn perpendicular to the common tangent at the point of contact, the line is called line of impact.

One dimensional collision or Direct impact:
Before and after collision, the colliding bodies centers of mass are traveling along the line of impact then that collision is said to be one dimensional collision.

Oblique Impact:   When the centers of mass of the colliding bodies are not moving along the line of impact, then the impact is called as oblique impact.