Question

When a body moves uniformly along the circle, then:
A. its velocity changes but speed remains the same
B. its speed changes but velocity remains the same
C. both speed and velocity changes
D. both speed and velocity remains same

Answer 1

Hint:Speed is basically the time rate at which an object is moving along a path whereas velocity depends on the rate and direction of the movement of an object.Speed is a scalar quantity but velocity is vector in nature.

Complete answer:
Velocity is commonly defined as the rate at which an object changes its position in a particular direction. It is a vector quantity. The velocity of an object changes with the change in its direction, so if an object moves in the same direction then its velocity will not change.As velocity depends on the direction so it can be zero, negative or positive depending on the situation.

Speed is defined as the rate at which an object covers a certain distance. It is a scalar quantity.The average speed will count irrespective of its distance change. In other words, the speed will continue to add up even if there is a change of direction.As Speed does not depend on direction so it can never be zero or negative. It will always be positive.Velocity and speed both are measured in $m/s$ (meters per second).

Here the body is moving uniformly in the circle so it is covering the same distance at every passage of time. That means, the speed will remain the same. So this implies that the speed remains constant while the velocity changes.

Hence, the correct answer is option A.

Note: An object can have different velocities but the speed will be the same all over because it does not depend on the direction.Speed gives an idea of the rapidity of the moving object. Velocity gives an idea about the rapidity as well as the position of the object in motion.