Billiards Consider the case where one ball is initially at rest pb cm before the final direction of the after red ball will depend on where the balls hit Physics 121: Lecture 16, Pg 16
Physics 121: Lecture 16, Pg 16 Billiards Consider the case where one ball is initially at rest. pa pb F Pa before after the final direction of the red ball will depend on where the balls hit. vcm
Billiards We know momentum is conserved: P=pa Pa p2=(pa +Pa)2=p 2+Pa2+2 pa Pa cos 0 We also know that energy is conserved 2m2m2m Comparing these two equations tells us that pa PaCos 0 =0 pa and must therefore be orthogonal! Z Or., one momentum must be zero Physics 121: Lecture 16, Pg 17
Physics 121: Lecture 16, Pg 17 We know momentum is conserved: pb = pa + Pa We also know that energy is conserved: Comparing these two equations tells us that: Billiards pb 2 = (pa + Pa ) 2 = pa 2 + Pa 2 + 2 pa Pa cos 2m P 2m p 2m p 2 a 2 a 2 b = + pa Pa cos = 0 and must therefore be orthogonal! Or … one momentum must be zero. pa pb Pa p p P 2 a 2 a 2 b = +