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zaal
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Homework Statement
Hi, I'm trying to determine g (very precisely) using a falling ball in non-vacuum. I'm using three laser beams (along the z-axis), they're detecting when the ball enters the beam and leaves it again. This will give me six different times. To only problem is that we don't know where the ball crosses the laser (probably not in the middle).
I think we have to know when the middle of the ball crosses the laser, and that is proving to be quite hard due to the complexity of the formula below. (If the speed would have been constant, the middle of the ball would cross the laser at t=(t1+t2)/2) but due to the acceleration of the ball that isn't the case).
Also the exact moment the ball is droped isn't known. So the first time you'll know is the moment the ball enters the first laser(so t1=0).
Homework Equations
Falling object experiancing air resistance:
[tex] \frac{dv(t)}{dt} = g - q v(t)^2 [/tex]
solution
[tex] v(t) = \frac{g} {\sqrt{g q}} tanh(\sqrt{g q} (t+c_1)) [/tex]
The Attempt at a Solution
I think the solution is to solve a system of equations using 8 know values (5 times (t1=0 so everything is relative to t1) and the locations of the 3 lasers). Eventually I'm trying to find g.
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