question_answer 25)

A stone of mass m tied to the end of a string is revolved in a vertical circle of radius R. The net forces at the lowest and highest points of the circle directed vertically downwards are:  

Lowest Point	Highest Point
(i) (ii) (iii) (iv)

  Here  (and ) denote the tension in the string (and the speed of the stone) at the lowest and the highest point respectively. Choose the correct alternative.  

Answer:

The alternative (i) is correct because the net force at the lowest point L is  and the net force at highest point H is .