Inertia is defined as

Inertia is defined as

• A. A resistance to change a state of motion
• B. The tendency to stop moving
• C. The force that accelerates gravity
• D. The energy of motion

Answer: (A)

Inertia is the property of matter that resists changes to its motion or its state of rest. An object at rest tends to stay at rest, and an object moving in a straight line at constant speed tends to keep moving that way unless a net external force acts on it. This resistance to change in motion is what inertia describes. The other ideas mix up what inertia is: it isn’t simply the tendency to stop moving, it isn’t a force that accelerates gravity, and it isn’t the energy of motion (that would be kinetic energy).

Inertia is the property of matter that resists changes to its motion or its state of rest. An object at rest tends to stay at rest, and an object moving in a straight line at constant speed tends to keep moving that way unless a net external force acts on it. This resistance to change in motion is what inertia describes. The other ideas mix up what inertia is: it isn’t simply the tendency to stop moving, it isn’t a force that accelerates gravity, and it isn’t the energy of motion (that would be kinetic energy).