The figure below shows two stars.Star A has a mass twice that of our Sun,while Star B has a mass four times that of our Sun.Which labeled point identifies the center of mass of the system?
A) A
B) B
C) C
D) D

Question

The figure below shows two stars.Star A has a mass twice that of our Sun,while Star B has a mass four times that of our Sun.Which labeled point identifies the center of mass of the system? 
A) A 
B) B 
C) C 
D) D

Quizplus · Accepted Answer

The center of mass of a binary star system is the point around which the two stars orbit. Since Star A has twice the mass of our Sun and Star B has four times the mass of our Sun, Star B exerts twice the gravitational force on Star A as Star A exerts on Star B. This means that the center of mass must be closer to Star B than to Star A. Therefore, the correct choice is point C, which is closer to Star B.

The Figure Below Shows Two Stars