Which quantity is a measure of particle motion in a medium?

Which quantity is a measure of particle motion in a medium?

• A. Distance
• B. Velocity
• C. Acceleration
• D. Displacement

Answer: (A)

Distance measures how far the particle travels along its path through the medium, reflecting how much motion has occurred. It accumulates as the particle moves, regardless of direction, so it directly quantifies the extent of motion. In contrast, velocity tells how fast and in what direction the particle is moving at an instant, acceleration describes how velocity changes, and displacement is just the net end-to-end change in position, which can be small even if a lot of movement happened. So distance is the clearest measure of how much motion occurred.

Distance measures how far the particle travels along its path through the medium, reflecting how much motion has occurred. It accumulates as the particle moves, regardless of direction, so it directly quantifies the extent of motion. In contrast, velocity tells how fast and in what direction the particle is moving at an instant, acceleration describes how velocity changes, and displacement is just the net end-to-end change in position, which can be small even if a lot of movement happened. So distance is the clearest measure of how much motion occurred.