The relationship between force and acceleration when mass is constant is directly proportional. This means that if you increase the force, the acceleration will increase proportionally, and if you decrease the force, the acceleration will decrease proportionally.

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

F = m * a

where:

* F is the force applied

* m is the mass of the object

* a is the acceleration of the object

In simpler terms:

* If you push an object with twice the force, it will accelerate twice as fast.

* If you push an object with half the force, it will accelerate half as fast.

Important Note: This relationship holds true only when the mass of the object remains constant. If the mass changes, the relationship between force and acceleration will also change.