Question

Two billiaard balls rolls to one another under an angle of 45°. Ball A have a speed of 3m/s and follows a track along the positive x-axis. Ball B moves on a track towards the x-axis and comes from the left top corner with a speed of 2m/s. Calculate the speeds and the directions of the tracks after the collision (complete elastic). there are two possible outcomes. tip: use an analytical methode.

Answer 1

I do not agree that there are only two solutions to this problem. You have four unknowns (two final speeds and two final direction angles) and only three equations (x-momentum, y-momentum and total KE). Also, in a real-world situation, there can be a collision that is "head-on" (as seen by one ball) or grazing. The line of centers at contact may or may not line up with the relative velocity vector. Both considerations allow an infinite number of possible solutions.

Answer 2

Dear drwls, could u put out the equations for me to have a better insight of what u explained above?
Thank very much