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Victorian91

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## Homework Statement

A star of mass M and radius r rotates with angular speed of such value that objects on the surface at its equator are just about to experience zero apparent weight. The period of rotation of the star is given by?

## Homework Equations

g' = g- Rw

_{2 (where w is the angular velocity) The Attempt at a Solution From the above.. mg' =mg -mRw2 Since apparent weight is zero, mg -mRw2 = 0 mRw2 = mg But w = (2Pi/T)^2 R ( 4Pi^2/T^2 ) T^2 = 4Pi^2 R/g But g = GM/R2 at the surface of the planet Hence, Period, T= 2Pi square root r3/G But the answer given is 2Pi square root r3/gM Why does the Mass of the star still have in the equation I tried so many times the Mass will be canceled out.. Do you think which one is correct?? Thanks}