Centripetal/Gravitational Force

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In the discussion about centripetal and gravitational forces, the focus is on two stars, A and B, orbiting a common center of mass with the same period T. The centripetal acceleration for star A is expressed as (4Raπ²)/T². The challenge lies in determining the mass of star B, which involves equating the centripetal force on star A to the gravitational force exerted by star B. The relationship between gravitational force and centripetal force is crucial for solving for mass without cancelling out variables. Understanding this relationship is key to progressing in the problem.
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Orbiting Bodies Question

2. Two stars, A and B are in circular orbits of radii ra and rb, respectively, about their common center of mass at point P. Each star has the same period of revolution T.

Determine expressions for the following three quantities in terms of Ra, Rb, T, and fundamental constants.

a. The centripetal acceleration of star A
b. The mass Mb of star B


F_g=\frac{GM_1M_2}{r^2}, a_c=\frac{4pi ^2r}{T^2}



I solved for Part a and got [(4)(Ra)(pi)^2]/T^2. Part b has me stumped though. I think it has to do with the relationship between Fg and Fc and/or the fact that the periods of the two planets are equal. But when I try to solve for the mass, I keep cancelling out the mass variable. If someone could just steer me in the right direction, I would greatly appreciate it. Thanks.
 
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Equate the centripetal force on A to the force exerted on it by B.
 
Right, that makes sense... I don't know why I didn't think of that. Thanks!
 
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