Question

Both earth and moon are subjected to the gravitational force of the sun. As observed from the sun, the orbit of the moon

• A. Will be elliptical.
• B. Will not be strictly elliptical because the total gravitational force on it is not centre.
• C. Is not elliptical but will necessarily be a closed curve.
• D. Deviates considerably from being elliptical due to influence of planets other than earth.

Answer 1

Answer: (B)

Will not be strictly elliptical because the total gravitational force on it is not centre.

Answer 2

Moon revolves around the earth in a nearly circular orbit. Sun exerts gravitational force on both, earth and moon. When observed from the sun the orbit of the moon will not be strictly elliptical because the total gravitational force on it (i.e. force due to earth on moon and force due to sun on moon) is not central.