Momentum loosely defined as “mass in motion.” Momentum is the tendency for objects to stay in motion once they are moving. The greater the mass or velocity of a moving object, the greater the momentum and the more difficult it is to stop.

Applied Concept: A skateboard in motion will eventually come to a stop. The faster the skateboard is moving, the longer it takes to stop. If someone is riding the skateboard and it hits a wall, the rider's momentum would continue to propel them forward. The heavier the rider, the more momentum the rider would have and the more difficult it would be to stop.

The momentum of a relatively light object:

…compared to the momentum of a relatively heavy object: