Some notes made during making the collision demo

Written by Nasser M. Abbasi

June 28, 2015
this page in PDF

Given 2 particles v,u  with velocity components as shown.


In elastic collision linear momentum in the x  and y  directions holds


In addition, kinetic energy is constant. Let v21 = (v21x +v21y) , v22 = (v22x + v22y),V12= (V12x + V12y) , V22= (V22x + V22y) then


We have 3 equations above, but 4 unknowns (V1x,V1y,V2x,V2y)  . The 4th equation comes from knowing that after collision, particles will travel at   0
90  trajectories.