Here's why:

* Newton's Second Law of Motion: This law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. This is represented by the equation: F = ma (Force = mass x acceleration)

* Inverse Relationship: The equation tells us that if the force (F) is constant, a larger mass (m) will result in a smaller acceleration (a).

In simpler terms: 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.