Question

The following quantities may remain constant during uniform circular motion :

• A. magnitude of acceleration
• B. acceleration
• C. speed
• D. velocity

Answer 1

Answer: (A), (C)

speed

Explanation of the correct option

A: Magnitude of acceleration

1. The magnitude of the acceleration is constant in a uniform circular motion, but their directions are not.
2. The magnitude is just a number and it does not have direction.

C: Speed

1. If a body is moving in a uniform circular motion, its speed remains constant.
2. Speed is a scalar quantity. so it does not have direction.

Explanation of the incorrect option

B: Acceleration

1. As acceleration is a vector quantity, it has direction and magnitude.
2. The direction of force varies at each point of a circular route (because force is directed towards the center), hence acceleration likewise changes at each point being directed towards the center, but its magnitude remains the same. As a result, acceleration isn't constant.

D: Velocity

1. As velocity is a vector quantity, it has direction and magnitude.
2. The direction of velocity in a uniform circular motion is along a tangent drawn to the particle's location on the circumference of a circle. As a result, the direction of velocity is constantly shifting.

Hence, options A, and C are correct.