The mass of Mars is 6.42 * 1023 kg. Its moon Phobos is 9378 kilometers away from Mars and has a mass of 1.06 * 1016 kg. What is the gravitational force between Mars and Phobos?

F = G*m*M / R²

F gravity in N

G gravitational constant = 6.6742 * 10⁻¹¹ m³kg⁻¹s⁻²

m mass of object 1 in kg

M mass of object 2 in kg

R distance between object 1 and object 2 in m

The gravitational force between two objects is determined using the formula:

F = (GMm) / r², where F is the gravitational force between the two masses, G is the gravitational constant (6.67*10⁻¹¹)

M and m are the masses of the two objects, and r is the distance between them.

Substitute the given values and note that r = 9378 km must first be converted to meters to be consistent with the units.

Thus, the gravitational force between Mars and Phobos is 5.16*10¹⁵ N.