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.

Question

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.

Answer 1

Wm/We = gm/ge = (GMm/rm^2)/(GMe/re^2) or Mm(re^2)/Me(rm^2).

Answer 2

Right. But w/o knowing the actual mass of the earth and moon, only the ratio, how can I do this?

Answer 3

Lindsay, you are given Mm/Me, and rm/re

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

Answer 4

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