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Math Jeans
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Homework Statement
Consider a particle of mass m constrained to move on the surface of a paraboloid whose equation (in cylindrical coordinates) is [tex]r^2=4az[/tex]. If the particle is subject to a gravitational force, show that the frequency of small oscillations about a cirrcular orbit with radius [tex]\rho=\sqrt{4az_0}[/tex] is
[tex]\omega=\sqrt{\frac{2g}{a+z_0}}[/tex]
Homework Equations
The Attempt at a Solution
I'm aware that the [tex]\omega[/tex] must come from the equation:
[tex]\ddot{x}+\omega x=0[/tex]
This DiffEq comes from [tex]F=m\ddot{x}[/tex], so we need [tex]F=-\frac{2gm}{a+z_0}[/tex].
The only definition of g goes to [tex]\frac{MG}{R^2}[/tex], so we must be looking for a force [tex]F=-\frac{mMG}{R^2}*\frac{2}{a+z_0}[/tex]
My attempt is based on looking at the radial component of a gravitational force pulling out of the plane along [tex]\hat{s}[/tex], however, every time, I get:
[tex]\vec{F}=-\frac{mMG}{S^2}\hat{s}[/tex], where the radial component would be [tex]\vec{F}\bullet\hat{r}[/tex]
In a nutshell...my answer keeps turning up wrong.