A tunnel is dug along a diameter of the earth. Find the force on a particle of mass m placed in the tunnel at a distance x from the centre.

Options

A. `(GM_(e)m)/(R^(3))`
B. `(GM_(e)m)/(R^(2))x`
C. `(GM_(e)m)/(R^(3)x)`
D. `(GM_(e))/(R^(3)x)`

Answer

A

Explanation

`F=(GM'm)/(x^(2))`but `(M')/(x^(3))=M/(R^(3))`