Assume that Ida's tiny moon Dactyl (see Question 36) has a density of \(2500
\mathrm{~kg} / \mathrm{m}^{3}\). (a) Calculate the mass of Dactyl in kilograms.
For simplicity, assume that Dactyl is a sphere \(1.4 \mathrm{~km}\) in diameter.
(b) Calculate the escape speed from the surface of Dactyl. If you were an
astronaut standing on Dactyl's surface, could you throw a baseball straight up
so that it would never come down? Professional baseball pitchers can throw at
speeds around \(40 \mathrm{~m} / \mathrm{s}(140 \mathrm{~km} / \mathrm{h}\), or
\(90 \mathrm{mi} / \mathrm{h})\); your throwing speed is probably a bit less.