Question 39

Neither speed nor velocity changes.

In this scenario, a runner maintaining a constant pace implies that both their speed and velocity remain consistent throughout the final straightaway. Speed refers to the magnitude of movement, while velocity includes direction; since the runner is not accelerating or changing direction, both quantities stay the same.

A) Both velocity and speed change.

This option is incorrect because if the runner is maintaining a constant pace, there is no change in either speed or velocity. Changes in these quantities would indicate acceleration or a change in direction, which is not the case here.

B) Speed changes, but velocity does not.

This option is also incorrect. If speed were changing, it would imply that the runner is either speeding up or slowing down, contradicting the premise of maintaining a constant pace. Therefore, both speed and velocity must remain unchanged.

C) Neither speed nor velocity changes.

This option is correct as it accurately reflects the situation of the runner maintaining a constant pace. Since the runner is not altering their speed or direction, both speed and velocity remain constant throughout the straightaway.

D) Velocity changes, but speed does not.

This option is incorrect because it suggests that while the magnitude of the runner's speed remains constant, the direction of their velocity changes. In a straightaway with a constant pace, there is no change in velocity, as both speed and direction are constant.

Conclusion

The correct answer is C, as it accurately describes the runner's situation of maintaining a constant pace where neither speed nor velocity changes. Options A, B, and D incorrectly suggest variations in speed or velocity, which do not occur when a runner is moving at a steady pace in a straight line. Thus, C is the only choice that aligns with the concept of constant motion.