Question

A merry-go-round is moving with a constant speed of $12m{{s}^{-1}}$, the girl sitting on it is,
A. at rest
B. moving with uniform velocity
C. in accelerated motion
D. moving with no acceleration

Answer 1

Hint: Velocity of a body can be found by taking the derivative of displacement with respect to time. Acceleration is found to be the derivative of velocity with respect to time. Velocity is a vector quantity which is both magnitude and direction. Keep this all in mind while solving this question.

Complete answer:
Speed is a scalar quantity which is the rate at which a body covers distance. By the way, velocity is found to be a vector quantity which means it is direction based. Velocity is given as the rate at which the position of a body varies. Here in this question, as the direction of motion of the girl sitting on the merry-go-round is constantly varying, even though the speed is being constant, the velocity at each instant is found to be varying. This vector quantity which is varying due to the change in direction of motion makes the body to have an acceleration. Therefore the girl sitting in a merry-go-round is found to be moving with an acceleration.

So, the correct answer is “Option C”.

Note:
The velocity of a body is given as the rate of variation in the position with respect to a frame of reference of a body, which is also a function of time. Velocity is similar to the specification of speed of an object and the direction of motion. The average speed is referred to the distance- time ratio which is also a scalar quantity.