Calculate the total mass of the galaxy lying within 20 kpc of the galactic center if the (circular) rotation speed at that radius is 240 km/s. (8 points) if the velocity increases with distance linearly, how does mass distance?

Choose a synonym for the underlined homonym (a word with two or more meanings). i did not expect the boat to rock so much. a. boulder c. astound b. sway d. shock

What sort of waves exhibit the doppler effect?

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.