The law that states that the acceleration of an object is determined by its mass and the net force acting on it is Newton's Second Law of Motion.

Here's the mathematical representation of the law:

F = ma

Where:

* F is the net force acting on the object

* m is the mass of the object

* a is the acceleration of the object

This law essentially tells us that a larger force will produce a larger acceleration, and a larger mass will result in a smaller acceleration for the same force.