1. Knows: Mass of Earth: `M_e = 5.97 times 10^(24)\ kg` Radius of Earth: `r_e = 6.37 times 10^6\ m` (a) Use above information to calculate the average density of the Earth. (b) Where does the value fit among those listed in Table 14.1. Look up the density of a typical surface rock like granite in another source and compare it with the density of the Earth.


Hint
`V=4/3πr^3` `ρ=m/V`
Answer
(a) `5.52 \times 10^3\ kg//m^3` (b) It is between the density of aluminum and that of iron and is greater than the densities of typical surface rocks.
Show Steps
(a) `V_e = 4/3π(6.37 times 10^6)^3 = 1.0827 times 10^(21) m^3` Density of Eearth: `ρ_e=(5.97 times 10^(24)kg)/(1.0827 times 10 ^21 m^3) = 5.52 times 10^3 kg//m^3`