is the relative velocity (in meters per second) between an observer on earth and a galaxy where the H-beta line of Hydrogen is measured to be 622 nm?...

What is the relative velocity (in meters per second) between an observer on earth and a galaxy where the H-beta line of Hydrogen is measured to be 622 nm? (The wavelength of the H-beta line as measured at rest in the laboratory is 486 nm.)3.How fast is the typical oxygen molecule (with a mass of 5.31e-26 kg) traveling when it is at a temperature of 440 Kelvins?4.Suppose you wish to measure the mass of a planet. To do so, you place a test mass in orbit around the planet at a distance of 6.6e+8 meters from the center of the planet. You find that the orbital period is 2.1e+5 seconds. What is the mass of the planet?