posted by aly .
One of the moons of Jupiter is Io. The distance between the centre of Jupiter and the centre of Io is 4.22 x 10^8 m. If the force of gravitational attraction between Io and Jupiter is 6.35 x 10^22 N, what must be the mass of Io?
You need to know the mass of Jupiter to do this problem.
Jupiter has a total mass of 1.9 x 10^27 kg.
Now use Newton's universal law of gravity to get the mass of Io.
Force = G*M(jupiter)*M(io)/R^2
G is the universal gravty cnstant.