A block at rest slides down a smooth inclined plane which makes an angle `60^(@)` with the vertical and it reaches the ground in `t_(1)` seconds. Another block is dropped vertically from the same point and reaches the ground in `t_(2)` seconds. Then the ratio of `t_(1) : t_(2)` is

Options

A. `1 : 2`
B. `2 : 1`
C. `1 : 3`
D. `1 : sqrt(2)`

Answer

B

Explanation

`L = (1)/(2) g cos 60^(@)t_(1)^(2)" "...(i)`
`L cos theta = (1)/(2) "gt"_(2)^(2)" "...(ii)`

`(t_(1)^(2))/(t_(2)^(2)) = (1)/(cos^(2)60^(@)) = (4)/(1)`
`t_(1) : t_(2): : 2 : 1`