Force is directly proportional to acceleration when mass is constant. This means that if you increase the force, the acceleration will also increase proportionally, and vice versa.

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

Here's how it works:

* If the mass is constant, the force and acceleration are directly related.

* If you double the force, you double the acceleration.

* If you halve the force, you halve the acceleration.

* The constant of proportionality is the mass.

* A larger mass will require a larger force to achieve the same acceleration as a smaller mass.

In simple terms:

Imagine pushing a shopping cart. If you push harder (more force), it will accelerate faster. If you push with less force, it will accelerate more slowly. This assumes the mass of the shopping cart remains the same.