Conservation of Momentum in Collisions. Help with plots

[VyRianS]

Homework Statement

This is an experiment involving colliding 2 gliders on an airtrack. Initial and final speeds are both recorded. I need to plot a graph that proves the Conservation of Momentum holds true, but I can't seem to get the correct Y and X axis variables. Assuming both masses m₁ and m₂ are known, how do I go about doing this?

Homework Equations

m₁v_1i + m₂v_2i = m₁v_1f + m₂v_2f

The Attempt at a Solution

This only thing I can think of is manipulating the equation so it looks like:

v_2f = (m₁/m₂)(v_1i - v_1f) + v_2i

Thus I'll be taking v_2f as my Y-axis, v_1i - v_1f as my X-axis. However, my constant is the variable v_2i, so this model will probably not work...

I'd appreciate all the help given, and thanks.

 

[BruceW]

Well, both of the initial velocities are constants.
So in your equation, y-axis is [itex]V_{2f}[/itex] and the x-axis is [itex]V_{1f}[/itex]. So the graph would show how the velocity of one glider depends on the velocity of the other.

 

[VyRianS]

I will be repeating this experiment 5 times, getting different initial speeds each time.

Can it still be graphed the same way, since v_is will be different each time?

 

[BruceW]

Well, for each repeat of the experiment, you could draw a different line on the graph.
Hopefully each of these lines will have the same gradient, but will intercept the axis in different places.

Edit: actually, If you are only recording the final velocities once for each experiment, then what I've said here won't be helpful, since you wouldn't get several lines, just points.

 

[BruceW]

maybe instead you could calculate [itex]m_1V_{1i}+m_2V_{2i} - m_1V_{1f} - m_2V_{2f} [/itex] for each experiment (which should be about zero) and use this as the y axis, and use experiment number as your x-axis. So then you should get 5 points, which should be roughly on the x axis.