- #1
cherioslover
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Homework Statement
The andromeda galaxy has a velocity of 250 km/s as it rotates. The observed mass is 1 x 10^42 kg. If the galaxy is roughly a circle with a diameter of 66,00 light years how much mass is not accounted for visibly?
Homework Equations
Fc=mv^2/R Fg=Gm1m2/R^2
The Attempt at a Solution
I know you're supposed to calculate the mass of the galaxy as well as a calculated speed, then divide the differences in masses by gravitational mass to find the percentage of mass missing, but honestly i can't seem to get it and there was no answer given :(
someone pleas be my hero :')