In the previous problem. If the bullet is moving with velocity `50 sqrt(2) m//s`, the maximum angle made by string with vertical is

Options

A. `60^(@)`
B. `45^(@)`
C. `sin^(-1) ((4)/(5))`
D. `cos^(-1) ((4)/(5))`

Answer

D

Explanation

`v = (u)/(25) = (50 sqrt(2))/( 25) = 2 sqrt(2) m//s`
`sqrt(2 gL) = sqrt( 2 xx 10 xx 2) = 2 sqrt(10) m//s`
`v lt sqrt( 2 gL)` , the block will oscillate like a simple pendulum.
`0 = v^(2) - 2 gL ( 1 - cos theta)`
`0 = 8 - 2 xx 10 xx 2 ( 1 - cos theta)`
`cos theta = (4)/(5) , theta = cos^(-1) ((4)/(5))`