Now for some 1D treatments of momentum. These are `(still) experimental! This one introduces the box: velocity and mass are the compensated quantities.
To compare two, you'll need two boxes.
Collisions might require multiple boxes to represent the momenta. Perhaps two before and two after. The screen is going to get full, so again compress the representations a little.
But a more restricted choice might be best, allowing the comparison of simple ratios of mass.
To see how this might play out, here is a slightly tweaked version, restricted to reasoning about situations where two objects collide and then stick together.
It’s designed to give a semi-quantitative tool for exploring the constraints for the collision rather than as an online calculator for figuring out a final velocity, given the initial velocities and masses.
So the diagram is open-ended in character, to promote exploration and discussion.