A binary star consists of two stars A (mass 2.2 M S ) and B (mass 11 M s ), where M S is the mass of the sun. They are separated by distance d and are rotating about their centre of mass, which

Question

A binary star consists of two stars A (mass 2.2 M S ​ ) and B (mass 11 M s ​ ), where M S ​ is the mass of the sun. They are separated by distance d and are rotating about their centre of mass, which is stationary. The ratio of the total angular momentum of the binary star to the angular momentum of star B about the centre of mass is

TestHub · Accepted Answer

L B ​ L Total ​ ​ = I B ​ ⋅ ω ( I A ​ + I B ​ ) ω ​ (as ω will be same in both cases) ​ = I B ​ I A ​ ​ + 1 = m B ​ r B 2 ​ m A ​ r A 2 ​ ​ + 1 = r B ​ r A ​ ​ + 1 (as m A ​ r A ​ = m B ​ r B ​ ) = 2.2 11 ​ + 1 ( as r ∝ m 1 ​ ) = 6 ​ ∴ The correct answer is 6 .

Physics - Gravitation Question with Solution | TestHub

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