Question

State whether true or false
A moving body can have non-uniform velocity and uniform speed at the same time.

Answer 1

Hint: Velocity is a vector quantity while speed is scalar quantity. Velocity depends on direction. Speed is independent of direction. Speed is defined as distance upon time in no particular direction. Velocity is the rate of change of distance in a particular direction.

Complete step by step answer:
The above statement is true because velocity depends upon direction but speed doesn’t. This means if a body is moving with a constant speed but changes direction in intervals then the body is said to be moving with a non- uniform velocity. For example, a body is moving in a circular path with a constant speed of 4ms$^{-1}$ (A Circular Motion). Although the speed is uniform but the direction of motion changes at every point of time so the velocity is non-uniform.

Additional information:
When a body is in motion, it moves in a straight line with constant velocity thus covering equal distance in equal interval of time irrespective of the duration of time is known as uniform motion.
When a body is in motion, it moves in different directions with changing velocities thus covering different distances in different intervals of time, irrespective of the time interval duration is known as non-uniform motion.
Acceleration of a body is non-zero only if it moves with varied velocity over a given interval of time.

Note: Students usually get confused between uniform motion and uniform acceleration. Uniform acceleration leads to non-uniform velocity and is not the same. In uniform motion, a body travels with a constant velocity. In uniform acceleration, a body travels with constant increase or decrease in velocity. Students might think the above statement is false if they think of speed and velocity to be the same but they differ on the basis of direction.