The weight of the atmosphere above 1 m2{\rm m}^{2} of Earth's surface is about 100,000 N{\rm N}. Density, of course, becomes less with altitude. But suppose the density of air were a constant 1.2 kg/m3{\rm kg}/{\rm m}^{3}.

Calculate where the top of the atmosphere would be.

How do I find atmosphere ?

3 answers

Weight per area is pressure, it is given as 100kPa/m^2 above.

but this weight would equal density*volume*9.8N/kg, or
density*1m^2*height*9.8

set that equal to 100kN/m^2, and solve for height.
24.5
8.3x10^3m