Just as I was two years ago, I am caught up in the bright pageantry of the Olympics, this time the Winter Olympics. I've written about the Olympics before, since this Electron Weblog is now over two years old. It seems that each Olympics I watch reflects on my different mood for that year. In summer 2004 I was full of hope and purpose, but now in winter 2006 I am chilly and stagnant. I watch the athletes in their triumphs (or failures) with a kind of "achievement lechery," thinking of how much dedication they have, how much support they receive, and how they succeed in just getting to the top competition, yet alone winning in it. And I compare it to my own lack of achievement, staring numbly at the physics page I cannot find the energy to turn, the painting I cannot find the energy to start. What is all this talk about "following your dream?"

Even though I grew up in a land of winter, I never took to winter sports. I tried skating, but I was klutzy, uncomfortable, and unbalanced, and I hated it. I think I put on skis once in my life, with the same results. The only sport I have ever had any skill at was tennis, and I haven't swatted a tennis ball in twenty years. As a kid, I enjoyed sledding, on rare occasions, and that was about the only snow fun I ever had. So when I look at those athletes in their brilliant superhero costumes doing all these daring things, I am in awe of anyone who is brave enough to ski down a mountain or leap and twirl on a skating rink, or slide up and down the curved near-vertical walls of the snowboarding "half-pipe" course. The ski and snowboard aerial acrobatics seem wildly unnatural compared to the more "natural" sports of the Summer Olympics such as running or jumping or swimming. Most anyone who is physically able can run or lift weights or swim at a modest level, but it takes a special kind of person to do ski jumping.

Naturally, I think of physics while I am watching the snowboarders go through their moves. The snowboarder has potential energy while she is at the top of the course. As she descends into the reverse barrel-vault of the course, she gains kinetic energy and speed. She has enough speed to go right up the vertical wall and fly into the air, in a more or less parabolic curve, since the coefficient of friction of the snow on her board is minimal. At the top of her aerial trajectory above the wall, she once again has potential energy but not kinetic; her turns in the air don't affect the total energy. Back down the wall she gains kinetic energy again so her run through the course is a constant see-saw of potential against kinetic energy. But as she moves, she is losing energy, to friction against both snow and air. When she reaches the end of the course, she stops by increasing the friction of the board against the snow. Winter sports are all about friction, or the lack of it on snow and ice. And it's nice to see the young, cheerful American athletes win gold medals in snowboarding physics.

Posted at 2:45 am | link