Here's why:

* Newton's Second Law of Motion: This law states that the force (F) acting on an object is equal to its mass (m) multiplied by its acceleration (a): F = ma.

* Rearranging the equation: We can rearrange this equation to solve for acceleration: a = F/m.

* Inverse Proportionality: This equation shows that acceleration is directly proportional to the force applied, but inversely proportional to the mass of the object.

In simpler terms:

* A larger mass will experience a smaller acceleration for the same force applied.

* A smaller mass will experience a larger acceleration for the same force applied.

Example:

Imagine pushing a small car and then a large truck with the same force. The car will accelerate much faster than the truck because it has less mass.