# Gravity Formula

Gravity Formula

Gravity is the Force of attraction between two objects times the gravitational constant, and inversely related to the square of the distance between the objects.

Force = [gravitational constant x masses (m1 x m2)] / (radius)2

F = [Gm1m2] / r2

F = force of gravity, N/kg

G = gravitational constant, 6.67 x 10-11 N-m2/kg2

m1 = 1st mass, kg

m2 = 2nd mass, kg

r = distance between the two masses, m

Gravity Formula Questions:

1) What is the gravitational force acting upon two objects of masses 15 g and 15 kg, that are 11 m apart?

Answer: the gravitational constant, G, is defined as 6.67 x 10 -11 N-m2/kg2 ; m1 = 15 g = 0.015 kg; m2 = 15 kg; r = 11m.

F = [Gm1m2] / r2

F = [6.67 x 10-11 N-m2/kg2 (0.015 x 15)kg] / (11 m)2

F = 1.24 x 10-13 N / kg

2) If the gravitational force between two objects is equal to 1.1 x10-11N/kg, and the masses are 6 kg each, what is the distance between them?

Answer: The force, F = 1.1 x 10-11 N/kg, and both m1 and m2 have masses = 6 kg.

G is defined.

F = [Gm1m2] / r2

r2 = [Gm1m2] / F

r2 = [ 6.67 x 10-11 N-m2M/kg2 (6 kg)(6kg)] / 1.1 x 10-11 N/kg

r2 = 2.18 x 10 -20 m2

r = √(2.18 x 10 -20 m2)

r = 1.48 x 10-10 m