Question

A solid sphere of mass \( M \), radius \( R \) exerts a gravitational force \( F \) on a point mass. Now a concentric spherical mass \( \frac{M}{7} \) is removed. What is the new force?

• A. \( \frac{F}{7} \)
• B. \( \frac{6F}{7} \)
• C. \( \frac{5F}{7} \)
• D. \( \frac{3F}{7} \)

Hint:

The gravitational force exerted by a sphere depends on the mass enclosed within a given radius, so removing a concentric spherical mass reduces the force proportionally.

Answer 1

The Correct Option is B

When a concentric spherical mass is removed, the gravitational force depends on the remaining mass within the sphere. 

The force is proportional to the mass, so the new force is \( \frac{6}{7} \) of the original force.