The asteroid, Ida, has a small moon, Dactyl, that orbits at a speed of 5.66 m/s in an orbit of radius 90, 000m . What is Ida's mass?

Answer:
4.3 x 10^16 kg
Explanation:
M = rv^2/G =[90,000 x 5.66^2] / [6.67 x 10^-11]
M = 43,226,446,776,611,694 = 4.3 x 10^16 kg - Ida's mass.