Momentum is a property of moving objects that depends on both their mass and velocity. It describes how difficult it is to stop an object in motion.
Impulse is the change in momentum of an object when a force acts upon it for a certain amount of time.
This principle states that in a closed system where no external forces act, the total momentum before an event is equal to the total momentum after the event.
An elastic collision occurs when two objects collide and bounce off each other without any loss of kinetic energy.