1. The problem: The moon Europa, of the planet Jupiter, has an orbital period of 3.55 days and an average distance from the center of the planet equal to 671,000 km. If the magnitude of the gravitational acceleration at the surface of Jupiter is 2.36 times greater than that on the surface of the Earth, what is the radius of Jupiter? (Hint: begin by calculating the rotation speed.) 2. Relevant equations F=GMjMm/R^2 v=2piR/T 3. The attempt at a solution Not sure at all. I guess, the centripital force of the mon Europa has to be equal to the gravitational force. MeV^2/R=GMeMj/R^2, but then I am not sure what to do with the given gravitational acceleration of Jupiter and how to get the r-radius of jupiter. I appreciate any help.