1. Net Force: This is the overall force acting on an object. It's the vector sum of all the individual forces acting on the object. A larger net force results in a greater acceleration.

2. Mass: This is a measure of an object's inertia, or its resistance to changes in motion. A larger mass results in a smaller acceleration for a given net force.

This relationship is described by Newton's Second Law of Motion:

F = ma

where:

* F is the net force

* m is the mass

* a is the acceleration