Question

Suppose a boy is enjoying a ride on a merry-go-round which is moving with a constant speed of $10m{{s}^{-1}}$. It implies that the boy is:
A. at rest
B. moving with no acceleration
C. in accelerated motion
D. moving with uniform velocity

Answer 1

Hint:Speed is a scalar quantity and velocity is a vector quantity. A vector quantity depends both on the magnitude and the direction of the quantity. So even if a scalar quantity is constant, the vector quantity can change depending on the direction changes or not.

Complete answer:
Speed of an object is a scalar quantity. It only has magnitudes but no direction. But velocity of an object is a vector quantity. It has both direction and magnitude.

In a merry-go-round, the objects move in a circular path around a round platform. As an object moves in a merry-go-round, the speed of the object may be constant, but the direction of the object changes with the motion of the object. Velocity of an object changes with the changes in speed or direction or both. Since, in a merry go round, even if the speed of the object is constant, the direction of motion of the object changes and the object will accelerate as, acceleration can be defined as the rate of change of velocity of the object.

We are given that a boy is enjoying a ride on a merry-go-round with a constant speed. According to the concept of velocity, the boy will be in an accelerated motion.

So, the correct answer is “Option C”.

Note:
The speed of an object is defined as the total distance covered by the object over an interval of time. The velocity of an object is defined as the total displacement covered by the object over an interval of time. Here also, distance is a scalar quantity and displacement is a vector quantity.