physics
posted by Brendan .
How would I graph a collision. i.e if I have a problem
A 12,000 kg railroad car traveling at a speed of 19 m/s strikes an identical car at rest. If the cars lock together as a result of the collision, what is their common speed afterward?
What would my x axis be and what would my y axis be ?

They are not asking you to graph the collision. All you need to do is apply a momentum conservation formula to compute a final speed.
The final speed is half the initial speed of the moving car.