Question

A stone of mass 'm' is rotated in a circular path with a uniform speed by tying a strong string with the help of your hand. Answer the following questions:

1. Is the stone moving with a uniform or variable speed?
2. Is the stone moving with a uniform or variable velocity?
3. Is the stone moving with a uniform or variable acceleration?
4. What is the effect of acceleration on the stone?
5. In which direction acceleration acts?
6. What kind of force is acting on the stone and state its direction?
7. What kind of force is acting on hand and state its direction?

Answer 1

1. The stone moves with uniform speed because its speed remains constant.
2. Its velocity is variable because the direction of motion changes at every point on the circular path.
3. Its acceleration is variable in direction. For uniform circular motion, its magnitude remains constant, but its direction continually changes as the stone moves around the circle.
4. The acceleration continually changes the direction of the stone’s velocity, keeping it in a circular path. It does not change the stone’s speed.
5. The acceleration acts towards the centre of the circular path.
6. A centripetal force acts on the stone, directed towards the centre. It is provided by the tension in the string.
7. The stone exerts an equal and opposite centrifugal reaction force on the hand, directed away from the centre along the string.