Which statement is correct about the relationship between the instantaneous speed and the magnitude of the instantaneous velocity?
A) The average speed can be less than, greater than or equal to the magnitude of the average velocity.
B) The instantaneous speed is always equal to the magnitude of the instantaneous velocity.
C) The average speed is always less than or equal to the magnitude of the average velocity.
D) The instantaneous speed is always greater than or equal to the magnitude of the instantaneous velocity.
E) The average speed is always one-half the magnitude of the average velocity.

Question

Quizplus · Accepted Answer

The magnitude of the instantaneous velocity is the absolute value of the instantaneous velocity, which is the speed with a direction. Therefore, the magnitude of the instantaneous velocity can never be less than the instantaneous speed, which is the scalar quantity without a direction. In other words, the instantaneous speed is always equal to or less than the magnitude of the instantaneous velocity, and they are equal only when the velocity vector points in the direction of motion (i.e., no change in direction). Option A and C are incorrect because they refer to average quantities instead of instantaneous ones. Option D is incorrect because it compares two different quantities, one with direction and one without direction. Option E is incorrect because it makes a generalization that is only valid under certain conditions.

Which Statement Is Correct About the Relationship Between the Instantaneous