1-D examples
In one dimensional collision cases, we can apply two laws: Conservation of Momentum and Conservation of Energy (here we assume there are no PE’s that change):
(1/2)m1v1i2 + (1/2)m2v2i2 =
(1/2)m1v1f2 + (1/2)m2v2f2 + Elost
m1v1i + m2v2i = m1v1f + m2v2f
These are two equations with 7 quantities:
m1, m2, v1i, v2i, v1f, v2f, Elost . Hence if we know five, we can solve for the other two.