The moon moves around the earth in a circular orbit and the earth moves around the sun in elliptical orbit then.
(a) For the earth - moon system, the gravitational attractions between them are the internal forces
(b) The sun.s attraction on the earth and moon are external forces acting on the centre of mass of the system.

Options

A. a is true, b is false
B. a is false, b is true
C. both a and b are true
D. Both A and B are false

Answer

C