How to Analyze a "Are These Values Equal?"
Is the momentum before the collision equal to the momentum after the
collision? Is the final mechanical energy equal to the initial
mechanical energy? These are important questions - how do we answer
them with, if not intelligence, then at least a little dignity?
Assuming that we have taken sufficient data, there are a couple of
- If two quantities are equal, then their difference is zero (or
their ratio is one). By making this one additional calculation,
the experiment can be converted into a "measure
the value of ..." experiment and analyzed as such.
- If two quantities are equal, a graph of one versus the other
is a straight line with unit slope and y-intercept zero. By
plotting the graph, the experiment can be converted into a
"is this proportional to
that..." experiment, and analyzed graphically.
So, which should you do? It wouldn't hurt much to do both, would
last update May 23, 2004 by JL