Im learming physics through google and I would like to be able to simulate some simple physics prgromatically. Having a hard time with solving for velocites after an elastic collision. Consider two objects, each with a mass of 1kg. One at rest and the other with velocity of 1 m/s in the direction of the first. Although total momentum in the system will be conserved after their collision, it seems there are an infinite number of possible velocities of the two objects after the collision that will satisfy the conservation of momentum; e.g., v1=0.5 m/s and v2=0.5 m/s; or v1=0.25 m/s and v2=0.75 m/s; or v1=-0.5 m/s and v2=1.5 m/s; etc. What additional piece of information or variable do I need to determine the one outcome in a given circumstance? Is it related to the elasticity of the materials? Is it the amount of time they spend in contact (i.e. impulse)?