Question

Estimate the mass of water on earth.(75% of the surface of earth is covered by oceans)

Answer 1

Dear Student ,
$$\begin{gathered} radiusofearth\left(R_e\right)=6400km \\ densityofwater=1000kg/m^3(assuminguniform) \\ volumeofearth=\frac{4}{3}\pi {R_e}^3 \\ and75\%ofthisvolume=\frac{3}{4}\times \frac{4}{3}\pi {R_e}^3=\pi {R_e}^3 \\ massofwater=volume\times density=\pi {R_e}^3\times 1000=.82\times {10}^{24}kg \end{gathered}$$
Regard