This is explained by Newton's Second Law of Motion:
F = ma
where:
* F is the force applied
* m is the mass of the object
* a is the acceleration of the object
If the force (F) stays the same, and the mass (m) increases, then the acceleration (a) must decrease to keep the equation balanced.
Think of it like this:
Imagine pushing a small car and a large truck with the same amount of force. The car will accelerate much faster than the truck because it has less mass.
