Question

A body performing uniform circular motion in a horizontal plane has a constant
A. Velocity
B. Acceleration
C. Kinetic energy
D. Displacement

Answer 1

In physics, when a body moves around a fixed point in a circular path with constant velocity in magnitude, such type of motion is known as uniform circular motion. We will discuss each given option to know about the characteristics of these parameters in uniform circular motion of the body.

Complete answer:
In uniform circular motion, the body moves in a circular path with the direction of its velocity at any point of path in the direction of tangent to the circle at that point, so velocity is a vector quantity whose direction always changes at each point during the motion.

Acceleration is also a vector quantity and such that acceleration is a derivative of velocity vector, and we know velocity changes at each point of path, so the acceleration will also change and hence it’s also not a constant quantity.

Kinetic energy which is written as $K.E = \dfrac{1}{2}m{v^2}$ which is the product of mass and square of the magnitude of velocity of the body, since mass and magnitude of the velocity is a constant value in case of uniform motion, so the magnitude of kinetic energy remains constant during the motion. So, Kinetic energy remains constant in uniform circular motion.

Hence, the correct option is C.

Note: It should be remembered that, Kinetic energy is a scalar quantity whereas velocity and the acceleration is a vector quantity whose direction continuously changes at each point of the circular path followed by the body in uniform circular motion and velocity and acceleration mathematically related as $\vec a = \dfrac{{d\vec v}}{{dt}}$.