More Musical Physics!

Talk about a busy musical weekend! Although I know that those in Youth Symphony had it even worse, I had Select Band tryouts early Sunday morning which took at least two and a half hours, and then a Christmas Concert in the evening, plus the Football game on Friday evening (Go Raiders!) and lots of practicing for my tryout. And I didn't realize until a few hours before the concert that I was using Physics with every note I played! Almost every note I play involves at least one of the four valves on my instrument, which consist of a metal rod with holes in it, a metal tube, oil to allow the valve to move, and a spring to return the valve to its unpressed position. When I press the valve, the spring force (-Kx, where x is the distance compressed from the spring's equilibrium point) is equal to the force my finger applies on the top of the valve. Thus the valve has a net force of zero, an acceleration of zero, and in this case a velocity of zero as well since it has reached the bottom of the tube. But when I am not using that valve, the spring force (for I seriously doubt that the spring is ever allowed to reach equilibrium while the valve is in its tube, otherwise the valve may not stay up and play correctly) is equal to the normal force of the valve on the cap keeping it in its tube. This senario is pictured above, with a very bad attempt to draw a spring, even though it was at least my fourth attempt. Since the oil attempts to keep the kinetic friction to a minimum, I wonder what the velocity of the valve is. However, I would need to take a few measurements, such as the greatest and least compression from equilibrium, and experiment to find the force constant of the spring. Perhaps I should do that. It could help answer some questions about why I have difficulty playing fast pieces. But I bet it won't; the instrument is not to blame for my slow fingers. :-)