Help distinguishing Mozart's 40 Symphony and Beethoven's 5th Symphony?

I have an art final tomorrow, and part of it is being able to identify a piece of music from a short clip. I'm having difficulty distinguishing between Mozart's Symphony #40 and Beethoven's Symphony #5- any tips? I'm not the most musical of people- i only know basic musical terms- so putting any explanations in layman's terms would be extremely helpful. Thanks!