# Angle of particles after elastic collision

1. Apr 1, 2009

### ajl1989

1. The problem statement, all variables and given/known data
A particle of mass M1 collides elastically with a particle of mass M2 at rest. Show that if M1>M2 then the angle of M1 after the collision cannot exceed the value arcsin(M2/M1).

2. Relevant equations
conservation of momentum: M1v1=M1v1+M2v2
conservation of kinetic energy: (1/2)M1v12=(1/2)M1v12+(1/2)M2v22

3. The attempt at a solution
I've figured out that the velocities after collision are:
v1=v1*[(M1-M2)/(M1+M2)]
and
v2=v1*[(2M1)/(M1+M2)]