To what is the rate of change in momentum directly proportional?

The rate of change in momentum is directly proportional to the applied force and takes place in the direction in which the force acts.

Explanation

Momentum is the quantity of motion and is compounded of the quantity of the matter moved, and the velocity with which it moves.

The law of conservation of momentum can be explained from the second law of motion. Newton’s second law of motion says that the rate of change of linear momentum of a body is equal to the net external force applied to it.

Mathematically it is expressed as:

$\frac{dP}{dt} \\=\frac{(mv)}{dt} \\=m\frac{dv}{dt} \\=ma \\=F_{net}$

If the net external force acting on a body is zero, then the rate of change of momentum is also zero, which means that there is no change in momentum.