This is a picture of our awesome tennis team last year. This past Saturday, I was playing tennis with my fellow teammates, Ali and Jamie. We had been practicing for about an hour when, much to my unhappiness, Coach Suzi ordered us to go and do sprints on the track. Great. I find running such an odious form of exercise, especially on a track. What is fun about running in circles??? That's right, NOTHING. Anyway, we had to obey orders, so off we went to purgatory. It was unbearably hot, but miraculously, I survived.

As I was running around the track for the billionth time, with my chest burning and what felt like a knife in my side, it occurred to me that I could use this for my physics blog I guess there was a silver lining to that very dark cloud after all. As we ran around the track, we ran with a constant velocity. However, periodically, we would sprint a certain distance. When we started to sprint, our kinetic energy increased. As we slowed down again, our kinetic energy decreased. Our potential energy stayed the same the entire time though. If the ground was where h=0, then our potential energy stayed at zero.

There was also air resistance acting on us as we ran around the track. As many of us have noticed however, the recent lack of trade winds is the cause for this hot weather, so there really wasn't too much air resistance. Nevertheless, there was air resistance. It was greatest when we sprinted, since air resistance increases with velocity, and least when we ran slowest, since air resistance decreases with velocity. I could figure out the work done by air resistance if I knew the force of the air resistance and how far we ran. Then I could solve for work using W = F cos (theta) * x. Since air resistance acts in the opposite direction, theta would be 180 degrees.

Yay for physics!