A particle is projected horizontally with a speed ''u'' rom the top of plane incline at an angle `theta` with the horizontal. How far from the point of projection will the particle strike the plane ?

Explanation

`R= sqrt(x^(2)+y^(2)) ((y)/(x)= tan theta)`
`= sqrt(x^(2)+(x tan theta)^(2))= x sqrt(1+tan^(2) theta)=x sec theta`
`x=ut, y=(1)/(2) "gt"^(2), (y)/(x)=(1)/(2)("gt"^(2))/(ut)`
`tan theta=("gt")/(2u),t=(2u)/(g) tan theta`
`x=ut=(2u^(2))/(g) tan theta " " :. R=(2u^(2))/(g) tan theta sec theta`