The planet earth has a volume of 1.1 x 1021 m³ and an average density of 5.5 g/cm³. What is the mass of earth in kilograms?

Question

The planet earth has a volume of 1.1 x 10²¹ m³ and an average density of 5.5 g/cm³. What is the mass of earth in kilograms?

Answer 1

This requires us to make a conversion of units so that the volumes are in the same units. We can opt to convert 1.1x10²¹ m³ into cm³ so it agrees with the units of the density.

1.1x10²¹ m³ x 1x10⁶ cm³ / m³ = 1.1x10²⁷ cm³

Now we can use the provided density to find the mass in g and kg:

1.1x10²⁷ cm³ x 5.5 g / cm³ = 6.05x10²⁷ g x 1 kg / 10³ g = 6.05x10²⁴ kg