Two inclined planes (I) and (II) have inclination alpha and beta respectively with horizontal (where `alpha + beta=90^(@)`)intersect each other at point O as shown in figure A particle is projected from point A with velocity u along a direction perpendicular to plane (I) If the particle strikes (II) perpendicularly at B, then:

Options

A. time of flight`=u//gsinbeta`
B. time of flight`=u//gsin alpha`
C. distance OB `=u^(2)//2gsinbeta`
D. distanceOB `=u^(2)//2gsin alpha`

Answer

A, C

Explanation

`X Y u_(x)=u u_(y)=0`
`a_(x)=-gcosalpha a_(y)=-gsinalpha`
`v_(x)=0`
`v_(x)=u_(x)+a_(x)t`
`:.t=u/(gcosalpha)=u/(gsinbeta)`
`o-u^(2)=2(-gcosalpha)S_(x)`
`:.S_(x)=u^(2)/(2gcosalpha)=u^(2)/(2gsinbeta)`