# Calculation of atmospheric presure

1. Sep 26, 2016

### Derek1997

1. The problem statement, all variables and given/known data
Taking atmospheric pressure at sea level to be 1x10^5 pa CPa and the density of air at sea level to be
about 1.2kg/m^3,estimate the atmospheric pressure in London 550m above sea level. For this calculation, it is easiest to assume that air density doesn’t change with height – briefly discuss
the validity of this assumption

2. Relevant equations
patm= rho g h

3. The attempt at a solution
Well, I did p=pgh- 1.2x9.8x550 and substracted the answer by the atmosperhic pressure of the sea to get the answer? Am I right?

2. Sep 26, 2016

### Bystander

Don't know, you haven't stated your result. It's certainly one way to "estimate" atmospheric pressure in London.

3. Sep 26, 2016

### Derek1997

Well alright thanks for reply.. here the results i got above
so for p atmospheric i got- 1.2kg/m^3x9.8m/s^2x 550m= 6648pa then i substractfrom the very given pressure that is 1x10^5pa-6648pa= 93352pa pressure of london?

4. Sep 26, 2016

### Bystander

You might want, in addition, to pay attention to significant figures.

5. Sep 26, 2016

### Derek1997

you mean i convert to kpa?

6. Sep 26, 2016

### Bystander

Not units --- significant figures.

7. Sep 26, 2016

### Derek1997

I don't understand. 93352pa= 92.5kpa?

8. Sep 26, 2016

### Bystander

Yes. I'll re-emphasize the "might," I've no idea how picky your instructor "might" be.

9. Sep 26, 2016

### Derek1997

Oh ok, thanks i gave u a like.

10. Sep 26, 2016