Explanation:
The gravitational force equation is the following:
[tex]F_G = G * \frac{m_1 m_2}{r^2} \\[/tex]
Where:
G = Gravitational constant = [tex]6.67408 * 10^{-11} m^3 kg^{-1} s^{-2}[/tex]
m1 & m2 = the mass of two related objects
r = distance between the two related objects
The problem gives you everything you need to plug into the formula, except for the gravitational constant. Let me know if you need further clarification.
