shminux comments on Questions for shminux - Less Wrong

-4 Post author: Thomas 22 June 2012 07:35PM

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Comment author: shminux 23 June 2012 05:37:44AM 1 point [-]

is it possible that this result was derived for a sphere?

This is quite general for isolated potential systems. Total energy of a particle: E=KE+PE. E=0 at infinity. KE=1/2mv^2, PE=mP where P is the gravitational potential (volume integral of -G*rho/r dV). Escape velocity corresponds to E=0, so we get v=sqrt(-2P), regardless of anything else.