3. A stone is tied to one end of a string. Holding the other end, the string is whirled in a horizontal plane with progressively increasing speed. It breaks at some speed because

a) Gravitational forces of the earth is greater than the tension in string

b) The required centripetal force is greater than the tension sustained by the string

c) The required centripetal force is lesser than the tension in the string

d) The centripetal force is greater than the weight of the stone

Ans: b) The required centripetal force is greater than the tension sustained by the string