A stone of mass 0.25 kg tied to the end of a string is whirled round in a circle of radius 1.5 m with a speed of 40 rev./min in a horizontal plane. What is the tension in the string ? What is the maximum speed with which the stone can be whirled around if the string can withstand a maximum tension of 200 N ?

Explanation

M = 0.25 kg r = 1.5 m
= `(40 xx 2 pi)/( 60) l "rad" //s`
For uniform circular motion centripetal force = tension
`(mv^(2))/( r ) = T`
`(0.25 xx 4pi^(2))/( 1.5)= T`
if 200 N tension is provided in the string speed should be such that string do not break
`:. (mv^(2))/( r ) = T `
`v^(2) = (1.5 xx 200)/( 0.25) `
`:. v= 34.64 ms^(-1) `