A boy whirls a stone of small mass in a horizontal circle of radius `1.5m` and at height `2.9m` above level ground. The string breaks and the stone flies off horizontally and strikes the ground after travelling a horizontal distance of `10m` . What is the magnitude of the centripetal acceleration of the stone while in circular motion ?

Options

A. 150 `ms^(-2)`
B. 140 `ms^(-2)`
C. `81.4 ms^(-2)`
D. 163 `ms^(-2)`

Answer

C

Explanation

`t=sqrt((2h)/(g))=sqrt((2xx8)/(9.8))=1.28s`
`v=(20)/(t)=15.63ms^(-1)`
`therefore" "a=(v^(2))/(R)=81.4ms^(-2)`