Two balls `A and B` are thrown with speeds `u and u//2`, respectively. Both the balls cover the same horizontal distance before returning to the plane of projection. If the angle of projection of ball `B is 15^@` with the horizontal, then the angle of projection of `A` is.

Options

A. `sin^(-1)((1)/(8))`
B. `(1)/(2)sin^(-1)((1)/(8))`
C. `(1)/(3)sin^(-1)((1)/(8))`
D. `(1)/(4)sin^(-1)((1)/(8))`

Answer

B

Explanation

R=const. `rArr u_(2)^(2)sin 2 theta_(2)`
`rArr sin 2 theta_(1)=(u_(2)^(2)sin2theta_(2))/(u_(1)^(2))=(u^(2)sin30^(@))/(u^(2))=(1)/(8)`
`2theta_(1)=sin^(-1)(1)/(8)rArr theta_(1)=(1)/(2)sin^(-1)(1)/(8)`