Two dimensional relativistic collision

Some Modern Physics and Special Relativity textbooks use a two dimensional collision of point particles to find the dependence of mass with velocity; however their figures are for non relativistic trajectories.
This program shows this relativistic collision from two reference systems: the laboratory and a rocket.
The program allows the selection of particle B (top one in each system) using the horizontal scroll bar. This velocity is taken the same as the one for the displacement of one system relative to the other.

The program also allows the selection of the rate at which the collision takes place; if it is less than 1.0, the process transcurs slowly, and greater than 1.0, faster. In this way we simulate the "projection" of a movie in which the frames per second can be varied.
It is posible to analyze the collision from other points of view: in a Minkowski diagram and in a non relativistic treatment.

Disponible en espaņol

Minkowski diagram | Non relativistic treatment

Instructions

The velocity of particle B (top in each system) is selected with the horizontal scroll bar.

The rate at which the motion takes place is selected with the vertical scroll bar.

Vel B is the velocity of particle B (top in each system) in the laboratory system.
v is the displacement velocity of one reference system with respect to the other.
rate Related to the frames "projected" per unit time in the rocket reference system.