In a collision momentum within any plane is always conserved. The total momentum of a system is constant, unless acted on by and external force.
What is conserved during elastic and non-elastic collisions ?
In Elastic collisions both momentum and Kinetic energy is conserved
In inelastic collisions momentum is conserved but kinetic energy is not conserved
What is centripetal force ?
Centripetal force is the resultant force (towards the centre) required by any mass to move in a circular path at a constant speed. (It is constant in magnitude, but keeps changing direction to point towards the centre. Therefore it does no work)
What is Angular Speed (ω) ?
The angle rotated per second in radians per second. (rad s^{-1})
ω= v=rω ω=2f
What is linear speed?
Tangential velocity at radius, r from the centre of rotation. (v=rω)