Are there any physics simulators where I can run a simulation of particles bouncing off each other?

Are there any physics simulators where I can run a simulation of particles bouncing off each other in an enclosed environment and measure the positions of those particles?

So I want to run a simulation in which particles start off in a clump in an enclosed, frictionless environment. The particles can bounce off of each other and off of the sides of the container. Each particle is assigned a variable velocity and random motion and after a certain time interval I want the particles to stop moving. Then I want to measure the distances of each particle to all the other particles and interpret the data. What's the best and simplest way to go about this?