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