## Question:

A ball is thrown onto a rough floor at an angle θ. If it rebounds at an angle φ and the coefficient of kinetic friction is μ, determine the coefficient of restitution e. Neglect the size of the ball. Hint: Show that during impact, the average impulses in the x and y directions are related by ${ I }_{ x }$ = μ${ I }_{ y }$ . Since the time of impact is the same, ${ F }_{ x }$Δt = μ${ F }_{ y }$Δt or ${ F }_{ x }$ = μ${ F }_{ y }$.