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09-11-2012, 11:54 AM   #12
UCSF2012
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Quote:
 Originally Posted by sstchur F = ma (force = mass x acceleration) That's not complicated physics. It's taught in any high school physics class. If you increase the mass of the racquet, and the a (acceleration) remains constant (that is, if you are capable of accelerating the racquet just as much after adding lead as you were before adding lead), then the F will be greater. You said "you know there's a problem with their 'physics' explanation just because it contradicts with what you find experimentally." If you are finding experimentally that after increasing the mass of the racquet, you are getting less power, then you are either not swinging as quickly as you were before, or your perception is off (not to mention is pretty high degree of error in one's ability to perceive a general increase or decrease in power, since they are so many variables at play in any given shot).
This is exactly what I'm talking about. Physics from the lay person who doesn't truly understand physics. Throwing around magic formulas in the wrong context doesn't say anything. All you idiots ever do is use buzz words and equations like F=ma to make you sound smarter.

This is a tennis ball hitting a racket. This is a COLLISION. You treat it as a collision by using impulse, I, not force, F. What's the difference? ....time. Impulse takes into account time. Specifically, the amount of time the ball sits on the string, not just the amount of force you place on the ball. When you lower the tension on a string, you increase the dwell time the ball sits on the stringbed. When you add lead, you're also changing the dwell time.

You're also dealing with efficiency. Moreso, how much of the racket energy you're imparting onto the ball. This is the most complicated topic, and you can't really calculate it. You have to measure it.

The whole problem is HUGE, and you idiots use the only formula you remember from high school physics, F=ma. And you demonstrate that you don't even know how to apply it.