The rate of change of momentum of a body is equal to the resultant:

According to Newton's Second Law of motion, the net or resultant force acting on an object is equal to the rate of change of its momentum. While Newton's law is often expressed as F = ma, its more general and powerful form states that the force applied to a system is equal to the time rate of change of momentum, mathematically represented as F = dp/dt. This relationship implies that an unbalanced force causes an object's motion to change, thereby causing its momentum to change over a specific time interval. In contrast, impulse is defined as the product of the average net force and the time interval over which it acts, which is equal to the total change in momentum rather than the rate of change. Therefore, the rate of change of momentum specifically defines the resultant force.