What term describes the resistance of a body to a change in its motion?

What term describes the resistance of a body to a change in its motion?

• A. Acceleration
• B. Momentum
• C. Inertia
• D. Energy

Answer: (C)

Inertia is the property that makes a body resist changes in its motion. Mass embodies this resistance: the more massive an object, the harder it is to speed up, slow down, or change direction, because a larger net force is needed to produce the same change in velocity. This idea is captured by Newton’s first law: an object at rest stays at rest, and an object in motion tends to continue moving in a straight line at constant speed unless acted on by a net external force. In flight, inertia explains why a heavier helicopter resists gusts and control inputs more than a lighter one—more force is required to alter its velocity. Momentum describes the quantity of motion (mass times velocity) rather than resistance itself, while acceleration is the rate of change of velocity, and energy relates to work and motion but not the resistance to change.

Inertia is the property that makes a body resist changes in its motion. Mass embodies this resistance: the more massive an object, the harder it is to speed up, slow down, or change direction, because a larger net force is needed to produce the same change in velocity. This idea is captured by Newton’s first law: an object at rest stays at rest, and an object in motion tends to continue moving in a straight line at constant speed unless acted on by a net external force. In flight, inertia explains why a heavier helicopter resists gusts and control inputs more than a lighter one—more force is required to alter its velocity. Momentum describes the quantity of motion (mass times velocity) rather than resistance itself, while acceleration is the rate of change of velocity, and energy relates to work and motion but not the resistance to change.