1. Calculate the orbital period for Jupiter's moon Io, which orbits from the center of the planet. 2. A white dwarf is a collapsed star with roughly the mass of the Sun compressed into the size of the Earth. What would be (a) the orbital speed and (b) the orbital period for a spaceship in orbit just above the surface of a white dwarf? 3 Given that our Sun orbits the galaxy with a period of 200 at a distance of from the galactic center, estimate the mass of the galaxy. Assume (incorrectly) that the galaxy is essentially spherical and that most of its mass lies interior to the Sun's orbit. and To how many Sun-mass stars is your estimate equivalent? 4 At what altitude will a satellite complete a circular orbit of the Earth in 1.8h ? thank you thank you!!!!!