Question

The weight of air column over an area of

1 cm2

on the surface of the earth is about :

(1) 1 kg wt. (2) 10 kg wt.

(3) 100 kg wt. (4) 1000 kg wt.

from this options ​

Answer 1

Explanation:

1033 g wt

Air pressure at sea level is about 101 000 Pa. A Pa (pascal), by definition, is a newton per square meter.

So the weight, force of that column which is 1 square meter in cross-section area is 101000 newtons.

There are 10000 cm² per m², so we get

the weight, force of that column 1 square cm in cross-section area is 10.1 newtons ⬅

Using F = ma or Weight = mass x acceleration of gravity,

10.1 newtons corresponds to a mass of 10.1 N / 9.8 = 1.03 kg ⬅

that is approximate and does not account for the weight decreasing as you go up in altitude. But most of the air is at low altitudes, so it's close.