Which of the following is true in uniform circular motion?

• A. Both the angular velocity and the angular momentum vary
• B. The velocity varies but the momentum remains constant
• C. Magnitude of both the velocity and the momentum stay constant
• D. The momentum varies but the velocity remains constant

In uniform circular motion, the object moves in a circular path at a constant speed. However, it's important to distinguish between speed and velocity. While the speed (magnitude of velocity) remains constant, the direction of the velocity changes continuously.

Key Points about Uniform Circular Motion

• Constant Speed: The speed of the object does not change.
• Changing Velocity: Since the direction of motion is always changing, the velocity vector is not constant.
• Angular Velocity: The angular velocity remains constant as the object moves around the circle.
• Angular Momentum: The angular momentum also remains constant if no external torques act on the system.

Correct Answer

The correct statement is C. Magnitude of both the velocity and the momentum stay constant. While the direction of velocity changes, its magnitude remains the same, and thus the momentum's magnitude also stays constant in uniform circular motion.