An iron ball of mass `m`, suspended by a light in-extensible string of length `l` from a fixed point `O`, is shifted by `theta_(0)` as shown so as to strike the vertical wall perpendicularly.The maximum angle made by the string with vertical after the first collision, if `e` is the coefficient of restitution, is

Options

A. `sin^(-1){1-e^(2)(1-costheta_(0))}`
B. `cos^(-1){1-e^(2)(1-costheta_(0))}`
C. `tan^(-1){1-e^(2)(1-costheta_(0))}`
D. zero

Answer

D

Explanation

F - f = ma
`alpha = (fR)/((2)/(5)mR^(2))=(5)/(2)(f)/(mR)`
`a = alphaR`
`(F)/(m) - (f)/(m) = (5f)/(2m) , f = (2F)/(7) = mu N`