We can solve for the critical density of the universe using the same method we used for finding the escape velocity. let's take an arbitrary point p in the universe, and consider a spherical shell of radius r0 around that point. according to hubble's law, an observer at point p will see a galaxy at point q on that spherical shell receding at velocity v=h0r0. what is the kinetic energy k of a galaxy of mass m at point q, relative to point p? express your answer in terms of h0, r0, and m. k =