Finding the mass of similar objects with GF given

Question

Two similar masses are 45cm apart, and experience a gravitational force of attraction of 1.59x10-13 N. What is the mass of each, in grams?

Answer 1

Well force = G m1 m2 / r²

G = universal gravitational constant (you can look it up)

m1 = m2 (as they are similar)

r = 0.45 m

And you know the force it's given

So you can solve for m1.

1.59 x 10^-13 = G m₁² / (0.45²)

So m₁ = √ (1.59 x 10^-13 x 0.45² / G)

Multiply m₁ by 1000 to get the mass in grams