What property of matter is responsible for resisting changes in motion or state of rest?

The property of matter that is responsible for resisting changes in motion or state of rest is inertia. Inertia is a fundamental concept in physics described by Sir Isaac Newton’s first law of motion, which states that an object at rest will remain at rest, and an object in motion will remain in motion at a constant velocity unless acted upon by an external force.

This means that the more mass an object has, the greater its inertia and the more force is required to change its state of motion—whether that means starting to move from rest, stopping, or changing direction. This quality of inertia is essential in understanding motion dynamics and is foundational in machine design, as it influences how components will behave under loads and stresses.

Friction, while it does play a significant role in motion by opposing it, does not solely describe the inherent property of matter to resist changes in motion. Brake systems are mechanisms that utilize friction to slow down or halt movement, and impulse pertains to a change in momentum due to a force acting over a time interval. Each of these concepts is important in their own right, but inertia specifically defines the tendency of matter to resist any change in its motion.