Friday, May 8, 2015

EJSS gravity 02_1

Example (N09/I/16) Binary Stars 

Two stars of mass M and 2M, at a distance 3x apart, rotate in circles about their common centre of mass O.
The gravitational force acting on the stars can be written as  k G M 2 x 2 .
What is the value of k?
A  0.22             B  0.50                C  0.67             D  2.0