There is, however, a special case of inelastic collisions in which we can
predict the outcome. Consider the case in which two particles collide, and
actually physically stick together. In this case, called a completely
inelastic collision we only need to solve for one final velocity, and the
conservation of momentum equation is enough to predict the outcome of the
collision. The two particles in a completely inelastic collision must move at
the same final velocity, so our linear momentum equation becomes:
| m1v1o + m2v2o = m1vf + m2vf |
|
Thus
In this equation M denotes the combined mass of the particles. Thus we can
solve for completely inelastic collisions, given the initial conditions.
In studying one-dimensional collisions we are essentially applying the principle
of conservation of momentum. The fact that many of these problems are soluble
speaks to the importance of this principle. From our understanding of
collisions in one dimension, we will move on to the two dimensional case, in
which the same principles are applied, but the situations themselves become more
complex.