What term describes an object whose displaced motion decreases in amplitude over time and returns toward equilibrium?

What term describes an object whose displaced motion decreases in amplitude over time and returns toward equilibrium?

• A. Positive dynamic stability
• B. Neutral dynamic stability
• C. Negative dynamic stability
• D. Instability

Answer: (A)

Dynamic stability describes how a system responds after a disturbance. When a system has positive dynamic stability, any small displacement produces motion that gradually dies away, so the object returns to its equilibrium position. This happens because damping forces remove energy from the motion, causing the amplitude to decrease with each cycle until it settles at the equilibrium. An example is a damped pendulum: nudged, it swings a bit and then slowly comes to rest as air resistance and friction dissipate energy. The described behavior—displaced motion that decreases in amplitude over time and heads back toward equilibrium—fits positive dynamic stability. If the amplitude stayed the same, it would be neutral; if it grew or diverged, it would indicate negative dynamic stability or instability.

Dynamic stability describes how a system responds after a disturbance. When a system has positive dynamic stability, any small displacement produces motion that gradually dies away, so the object returns to its equilibrium position. This happens because damping forces remove energy from the motion, causing the amplitude to decrease with each cycle until it settles at the equilibrium. An example is a damped pendulum: nudged, it swings a bit and then slowly comes to rest as air resistance and friction dissipate energy. The described behavior—displaced motion that decreases in amplitude over time and heads back toward equilibrium—fits positive dynamic stability. If the amplitude stayed the same, it would be neutral; if it grew or diverged, it would indicate negative dynamic stability or instability.