Which fixed property determines a body's resistance to changes in motion?

Which fixed property determines a body's resistance to changes in motion?

• A. Rigid body
• B. Mass
• C. Force
• D. Static body

Answer: (B)

Inertia—the resistance of an object to changes in its motion—depends on mass. Mass measures how much the object resists acceleration when a net external force is applied. According to Newton’s second law, acceleration equals force divided by mass (a = F/m). This means that for the same applied force, a heavier object (larger mass) experiences a smaller acceleration. To achieve the same change in motion for a heavier object, you need more force. Mass is intrinsic to the body, not dependent on its speed or location in classical mechanics. The other terms describe shapes, states, or causes of motion, but they don’t quantify that inherent resistance. So mass is the fixed property that determines how strongly a body resists changes in its motion.

Inertia—the resistance of an object to changes in its motion—depends on mass. Mass measures how much the object resists acceleration when a net external force is applied. According to Newton’s second law, acceleration equals force divided by mass (a = F/m). This means that for the same applied force, a heavier object (larger mass) experiences a smaller acceleration. To achieve the same change in motion for a heavier object, you need more force. Mass is intrinsic to the body, not dependent on its speed or location in classical mechanics. The other terms describe shapes, states, or causes of motion, but they don’t quantify that inherent resistance. So mass is the fixed property that determines how strongly a body resists changes in its motion.