1. Ganymede, one of Jupiter's moons, revolves around that planet at a distance of 6.64105 miles, with a period of about 172 Earth hours. Use this data to approximate the mass of Jupiter. 2. Four identical masses of 2.5 kg each are located at the corners of a square with sides of length 1.0 m. What is the net gravitational force (magnitude and direction) on the mass lying at the northeast corner of the square?