* Newton's First Law of Motion: An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

* Newton's Second Law of Motion: The acceleration of an object is directly proportional to the net force acting on the object, and inversely proportional to its mass. This can be represented as F = ma (Force = mass x acceleration).

Explanation:

* Applied Force: A force applied to an object directly causes a change in its acceleration. If the force is constant, the acceleration will also be constant. If the force changes, the acceleration will change.

* Mass: While mass is a factor in determining acceleration (F = ma), it's not the direct cause of a change in acceleration. A constant mass will have a constant acceleration if the applied force is constant.

* Air Resistance: Air resistance is a type of force that opposes the motion of an object through the air. It can change the acceleration of an object, but it's not the sole cause of change in acceleration.

* Change in Mass: A change in mass will affect the acceleration of an object, but only if the applied force remains constant. If the mass increases, the acceleration will decrease, and vice versa.

In summary: The acceleration of an object remains constant *unless* there is a change in the net force acting on it. This is the fundamental principle behind Newton's laws of motion.