A ball is projected with velocity u at right angle to the slope which inclined at an angle `alpha` with the horizontal. The distance `x` along the inclined plane that it will travell before again striking the slope is-

Options

A. `(2u^(2))/g cos alpha`
B. `(2u^(2))/g tan alpha`
C. `(2u^(2))/g (tan alpha)/(cos alpha)`
D. `(2u^(2))/g (tan alpha)/(sin alpha)`

Answer

C

Explanation

Equation for motion perpendicular to the incline `rArr u.t (1)/(2)-g cos alpha t_(2) rArr t = (2u)/(g cos alpha)`
Along incline
`x=0+(1)/(2)x(g sin alpha)((2u)/(g cos alpha))^(2)`
.