Momentum is the product of an object's mass and velocity. It describes how difficult it is to stop a moving object. A heavy truck moving slowly can have more momentum than a fast tennis ball.
A 70 kg person runs at 6 m/s. What is their momentum?
m = 70 kg v = 6 m/sp = m × v = 70 × 6The total momentum of a closed system remains constant — momentum before a collision = momentum after. This is one of the most important laws in physics.