Asked by Lindsay

Suppose that the ratio of the Moon's mass to the Earth's mass is given by 1.200E-2 and that the ratio of the Moon's radius to the Earth's radius is given by 2.700E-1. Calculate the ratio of an astronaut's Moon-weight to Earth-weight.

Now it seems like this problem really shouldn't be too difficult. However, I'm not sure of how to solve it given ratios instead of the actual masses and radius's.
Answered by tchrwill
Wm/We = gm/ge = (GMm/rm^2)/(GMe/re^2) or Mm(re^2)/Me(rm^2).
Answered by Lindsay
Right. But w/o knowing the actual mass of the earth and moon, only the ratio, how can I do this?
Answered by bobpursley
Lindsay, you are given Mm/Me, and rm/re

Wm/We= Mm/Me * (re/rm)^2

Answered by Lindsay
Ohhh I see now! Sorry, I just wasn't understanding before.
Thanks. :)