Length of a simple pendulum is 2m and mass of its bob is 2 kg if the tension in the string exceeds 100 N , it will break . If g =`ms^(-2) `and the bob is whirled in a horizontal plane , the maximum angle through which the sting can make vertical during ratating is

Options

A. `cos^(-1)(2//5)`
B. `cos^(-1)(5//2)`
C. `cos^(-1)(2//10)`
D. `cos^(-1)(1//10)`

Answer

C

Explanation

From the figure
`T cos theta=mg `
`therefore" "cos theta=(mg)/(T) =(2xx10)/(100)=(2)/(10)`
`therefore" "theta=cos^(-1) 2/10`
`therefore " "theta=cos^(-1) ""(2)/(10)`