Question

Can a body have a constant speed and still be accelerating?

Answer 1

Hint: For this solution, we will use the properties of speed, velocity, and acceleration which are basic quantities of motion of an object. Speed is a scalar quantity while velocity is a vector quantity.

Complete answer:
To answer this question, let us consider a few representative cases of motion.
If a body has constant velocity, it means that the magnitude of the velocity and the direction of the velocity vector will remain constant. Since speed is equal to the magnitude of the velocity vector, it will also be constant. Again, since the acceleration is the rate of change of velocity of a body with time, if the velocity is constant, the acceleration of the body will be zero.
A body can move with a constant speed but can have a changing velocity due to a change in its direction. For example, a car going on a roundabout can have a constant speed but since it will have a constantly changing direction, it can have a varying velocity as velocity is a vector quantity and depends on the direction of the car.
Hence, a body can have a constant speed and still be accelerating.

Note: All circular motions where the object is moving with constant velocity are a great example of cases where the body will have constant speed but it will be still accelerating since the velocity changes due to a change in direction of the object. Acceleration is related to the rate of change of velocity with time and not the speed of the object and we must be careful to not confuse the two.