A ball strikes a wall with a velocity `vecu` at an angle `theta` with the normal to the wall surface. and rebounds from it at an angle `beta` with the surface. Then

Options

A. `(theta+beta)lt90^(@)` if the wall is smooth
B. if the wall is rough , coefficient of restitution `=tanbeta//costheta`
C. if the wall is rough, coefficient of restition
`lttanbeta//cottheta`
D. none of these

Answer

A, C, D

Explanation

If wall is smooth `vcosalpha=eucostheta`
`vsinalpha=usintheta`
`cotalpha=eucottheta`
`alphagttheta`
`alpha+betagttheta+beta`
`90^(@)gttheta+beta`
If wall is rough, then `vcosbetaltusintheta`………….i
`vsinbeta=eucostheta`…..ii
From i and ii `egttanbeta/cottheta`