1. The problem statement, all variables and given/known data In the Bohr model of the hydrogen atom, the electron revolves around the nucleus. If the radius of the orbit is 5.8 z 10^-11 m and the electron makes 6.6 x 10^15 r/s, find; a) the acceleration of the electron b) the magnitude of the gravitational force of attraction between the electron and the nucleus c) the centripetal force acting on the electron d) the magnitude of each force contributing to the centripetal acceleration (name each force) 2. Relevant equations Fc= ma= mv^2/r=4pi^2Rf^2 Fg=Gm1m2/r^2 3. The attempt at a solution So I got the acceleration by using this equation: ac=4pi^2Rf^2= 9.97 x 10^22 m/s/s, and I know that the two forces contributing to the Fc are Fg and an electrical force of attraction. I do not know how to get the gravitational force of attraction without any masses. I'm at a loss. I also calculated the speed, but I do not see how I can use that to get the Fg and the Fc. Please help!