Question 39

Neither speed nor velocity changes.

In this scenario, the runner maintains a constant pace, which indicates that both their speed and velocity remain unchanged throughout the final straightaway.

A) Both velocity and speed change.

This option is incorrect because if the runner maintains a constant pace, there cannot be any change in either speed or velocity. A change would imply an increase or decrease in how fast the runner is moving or a change in direction, neither of which occurs in this scenario.

B) Speed changes, but velocity does not.

This option is also incorrect. If the runner's speed is changing, it would imply that the pace is not constant. Since velocity is a vector quantity that includes direction, if speed were changing, velocity would also change as a result.

C) Neither speed nor velocity changes.

This is the correct option. The runner is maintaining a constant pace, meaning that their speed (how fast they are going) and velocity (which includes both speed and direction) do not change as they run down the straightaway.

D) Velocity changes, but speed does not.

This option is incorrect because if velocity changes, it implies that there is a change in either the speed or the direction of motion. Since the runner is maintaining a constant pace, there is no change in either speed or direction.

Conclusion

The correct understanding is that when a runner maintains a constant pace, both speed and velocity remain constant as well. All other options incorrectly suggest that either speed or velocity is changing, which contradicts the premise of maintaining a constant pace. Thus, option C is definitively the right choice.