A Ball with mass Mo froms H1(Total Height),before it hits the ground it bounces off a stationary inclined plane at height (H2) with angle (Ω), it falls a distance of (H2) and travels a distance (L) over a time (∆t) FIND L and ∆t Image of Problem: http://s9.postimage.org/4xn9jpklb/Velocity.png (this is my verbal expression of the question, there will be a picture attached) unfortunately there was no written part to this question. am only having problem with one part specifically.... Which is the part i assume everyone has problems on.. The collision between the inclined plane, or how exactly to find the velocity after it has been reflected by the inclined plane. (I know the angle of reflection is = to angle of incidence) so therefore angle Ω of the plane is equal to angle Ω of the velocity after collision... I know that Px=Px' momentum is conserved in the X direction... My Attempt: Et1= Eg1=mgh1 Et2= Eg2 + Ek2 = mg(h1-H2) + 1/2MoV2^2 So Et1=Et2 mogh1=mog(h1-h2) +1/2MoV2^2 (masses cancel) V2 = Sqrt 2gh1-2g(h1-h2) (V2 is the velocity just before it collides with the plane) Now i've Drawn a FBD (my frame of reference/axis is along the surface horizontally and vertically the positive direction is towards the normal force) of when the ball is on the inclined plane (and it hits the plane so the normal force is perpindicular to the surface) so when i do my net forces i get fnetx= fgsinΩ fnety= fn -fgcosΩ=0 (therefore fn = fgcosΩ) Now i'm curious am i confusing this part, am i supposed to take the Normal force as the one which has components? Also when i do... this is where i get really stuck.. MOMENTUM!!! p=p' Since the inclined plane remains stationary during collison that means its vertical and horizontal compenents are both zero... let v2x =v2cosΩ v2y = v2sinΩ so im left with 0 + mov2x = 0 + mov2x' and 0 + mov2y = 0 + mov2y' so now components are equal but when i continued with these steps and showed my teacher the answer she said it was incorrect.... could someone please help me with Collision between an inclined plane and the ball and finding the velocity after the collision.. i have been working on this question for weeks, my semester for physics gr12 finished 3 weeks ago.. but i really want to answer this question.