Find the differential equation and velocity

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Alexiy
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Homework Statement


Diagram of a particle P on a horizontal chord AB of a circle centred at O, with radius R, perpendicular distance d from O to the chord, and a force F directed from P toward O; C is the midpoint of the chord on the y-axis.


Homework Equations


3. The Attempt at a Solution [/B]
Handwritten-style typed derivation of horizontal motion: y = d constant, force F = f(r) r/|r| with r = sqrt(x^2+d^2) and r vector = -(x i + d j), leading to mx'' = -kx/(x^2+d^2).
Hello guys,I posted images since its easier to write equations.Please can someone help me check this, if this is correct so far, then i should be able to find the velocity at C, using kinetic energy?
 
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Chestermiller said:
Looks good to me.
Typed mathematical derivation of kinetic energy and work done from A to C, computing an integral of -kx/(x^2+d^2) and concluding v_c = sqrt((2k/m) ln(R/d)).


Edit: Work done from A to C is the difference of the potential energy between these two points, am i wrong?
 
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By the way in the problems text i translated R as circumference, but its actually a radius R.
 
In my judgment, you did all this correctly. I think you should have more confidence in your ability. Your analysis was very nice, perceptive, and mathematically talented.

Chet
 
Chestermiller said:
In my judgment, you did all this correctly. I think you should have more confidence in your ability. Your analysis was very nice, perceptive, and mathematically talented.

Chet
Thank you very much Chet, I can't help it,I always had some difficulties to translate "physics thoughts" into math language so maybe I am overly cautious, sometimes i even waste time writing code for motion simulations to make sure something behaves like its supposed to, but it seems I'm getting the hang of it.Thanks again for your support.