Momentum is the product of an object's mass and velocity, p = mv.A resultant force acting for a time changes an object's momentum: the change in momentum equals the force x the time the force acts for. For example, a moving object's momentum equals the force needed to bring it to rest x the time that force acts for.Newton's second law states that the rate of change of momentum is directly proportional to the resultant force on an object and is in the same direction as the force.
over small timescales.Over large timescales average changes can be used so:
| F = | dp dt | = d(mv) dt |
| F = | Δp Δt |