In uniform circular motion the following quantities remain constant-

Correct option is A

The correct answer is (a) speed.

In uniform circular motion:

1. Speed remains constant:

   • The object moves at a constant distance from the center of the circular path, and its magnitude of motion does not change.

2. Velocity does not remain constant:

   • Velocity is a vector quantity that depends on both magnitude and direction.
   • Since the direction of motion changes continuously along the circular path, velocity is not constant.

3. Momentum changes:

   • Momentum is the product of mass and velocity.
   • Since velocity changes due to its changing direction, momentum also changes in uniform circular motion.

4. Acceleration is present:

   • Acceleration is always directed toward the center of the circle (centripetal acceleration).
   • It is responsible for continuously changing the direction of velocity, even though the speed remains constant.

Thus, speed is the only quantity that remains constant in uniform circular motion.

Additional Information:

• Speed: The scalar magnitude of motion along a circular path, constant in uniform circular motion.
• Velocity: A vector quantity that changes continuously due to the change in direction.
• Momentum: Dependent on velocity, hence changes as velocity changes.
• Acceleration: Exists due to the centripetal force acting toward the center, constantly changing the velocity’s direction.