Force. According to Newton's second law of motion, the acceleration of an object is directly proportional to the net force acting on the object, and inversely proportional to the mass of the object. In other words, the more force that is applied to an object, the greater its acceleration will be; and the more massive an object is, the less its acceleration will be for a given amount of force.

Mathematically, Newton's second law can be expressed as:

$$F = ma$$

Where:

* F is the net force acting on the object (in newtons)

* m is the mass of the object (in kilograms)

* a is the acceleration of the object (in meters per second squared)