In a class I have, the professor has offered extra credit for 1 page paper on a topic in Calculus 3 that has an application in the real world. I know calculus is used a lot in physics but I do not know physics very well.
What is a good topic that is understandable to a layman and that I might write an essay on?
You could look at Lagrange Multipliers, which is a method of optimisation for functions of several variables subject to some constraints.
http://en.wikipedia.org/wiki/Lagrange_multiplier