# Homework Help: Total mass of the earth's atmosphere

1. Nov 9, 2009

### lydigihome

1. The problem statement, all variables and given/known data

given: atmospheric pressure near the earth's surfact=100kPa
density of the air near the earth's surfact=1.3kg/m-3

the best estimate for the total mass of the earth's atmosphere:

5x1018 kg.

how to work out this value??

2. Relevant equations

I don't know..

3. The attempt at a solution
I don't know..

2. Nov 10, 2009

### Vaal

One kPa is a kN/m2. That means that for every m2 of the earths surface there must be 100kN of atmospheric weight. Convert this force into mass using F=ma (the atmosphere is thin enough that you can assume a=9.8m/s2 for its entirety and still get a reasonably accurate answer) and then multiply that mass by the total surface area of the earth to get the total mass. Also, you are going to have to make sure your units work out as there are a few kilos in there that could mess things up.

Hope this didn't come too late.