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**EXAM QUESTION black hole force??**

## Homework Statement

good morning everyone! just getting some last minute studying in before my final exam :(

ran into a question so hoping some one will help me understand it.

A star is observed to be in circular motion about a supermassive black hole at the center of

our galaxy. The radius of this orbit is 10^14 m (no prefix just 10 to the 14), and the period is T=15 years = 4.7 x 10^8s. If this

star has the mass of our Sun (M=2.0 x 10^30 kg), what is the magnitude of the force of gravity acting on it?

A. 4.9 x10^28 N

B. 3.6 x10^28 N

C. 2.0 x10^28 N

D. 1.3 x10^28 N

E. 8.8 x10^27 N

F. 6.5 x10^27 N

## Homework Equations

F = (Gm1m2)/r^2

G = 6.7 x 10^-11

## The Attempt at a Solution

i started using the formula but we do not know the final force (what we are trying to solve for) OR the mass of the black hole. two unknows and only one equation. i have to be missing something. any help would be great!!!

thanks