Question

A stone tied to a thread is moved with a constant speed of 10 m/s along a circular path but still its motion is said to be accelerated. Why ?

Answer 1

Explanation:

The stone experience a radial force which keeps on changing the direction of motion of stone without changing its speed. But there is a change in velocity, Therefore it is called an accelerated motion.

Answer 2

Acceleration is the rate of change of velocity and velocity depends on the direction.....so in this case you see the body's direction is changing constantly.....so the velocity will change and so will the acceleration. The speed in turn will remain constant as it does not depend on direction. We can say thus that speed is a scalar quantity i.e. it only has magnitude but velocity is a vector quantity as it has both direction and magnitude.