Question

when the particle performs UCM, in a horizontal circle, which physical quantity associated with its motion does not remain constant?

Answer 1

velocity- it changes direction

acceleration- it changes its direction so that it stays towards centre

Answer 2

When a particle performing UCM in a horizontal circle the physical quantity that does not remain constant is velocity

• When a body moves in a circle at a constant speed, every point of its motion experiences a change in velocity.
• Only the direction, not the magnitude, of this velocity has changed.
• Let's now examine each choice separately.

Speed-it remains constant as the motion is uniform circular motion.

Kinetic energy(E), E= ½ mv² ........ (1)

Where, m=mass of the body

v=speed with which the body is moving

Since speed is constant. So, kinetic energy will also remain constant.

Linear momentum(P), P= mv ....... (2)

The magnitude of linear momentum will also remain constant.

• Velocity- The body's speed varies in direction at every point along the track, therefore it does not move in a uniform circle at a consistent rate.

Hence, when a particle performing UCM in a horizontal circle the physical quantity that does not remain constant is velocity.

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