The formula to calculate the gravitational force between two objects is F_g=GM_1M_2/r^2, where M_1 and M_2 are the masses of the objects, G is the gravitational constant and r is the distance between the objects. Solve for M_1 in terms of F_g, G, M_2 and r.

=

Step-by-step explanation:

From Newton's law of universal gravitation, the force of attraction between two objects of masses and is given as:

=

Thus, cross multiply to have;

= G

then divide through by G to have,

=

Therefore, can be expressed in terms of , , G, as