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Homework Statement
Is it possible to calculate the mass of the Milky Way knowing only the speed of a planet in a circular orbit? I fail to see how, but if yes, then how?
Thanks in advance
Well, in a circular orbit,well there's only one force acting on a something out in space (most of the time, let's just assume this is the case)
so if F_{net} = F_{g}
can you take it from there?
Exactly. If you don't have the radius, then you can't get the speed. You would need to find the radius some other way, or introduce other assumptions.Well, in a circular orbit,
F_{centripetal}=F_{g}
You are given only the speed v. The problem is how to get rid of the radius (r). Dunno how, and if possible.
Could you elaborate on this please? Seems interesting, but dont think I follow. What kind of trend and how do you work out the radius from that?for example, you could assume that the star fits the typical trend of other stars in orbit around the milky way, then you could work out the radius of the star.