How to Calculate the Total Mass of Earth's Atmosphere Using Physics Modelling?

In summary, the conversation discusses the variation of density in the Earth's atmosphere with height, using the equation p = p(o) exp(-r/r(o)). It also attempts to estimate the total mass of the atmosphere, taking into account that most of the mass lies within a distance much smaller than the radius of the Earth. The conversation presents two different approaches to solve the problem, but neither is able to address the issue of dealing with the much greater than part of r(earth) >> r. A solution is not reached and the conversation ends with a request for help.
  • #1
Spoony
77
0
so I am tearing my hair out with this one...

the density of the Earth's atmostsphere vaires with height r above the Earth's surface as

p = p(o) exp(-r/r(o))

where p(o) the density of the air at ground level, is 1.3 kg/m^3 and r(o) the scale height is 8km
use this to estimate an approximate value for the total mass of the atmostsphere, given most of the mass lies within a ddistance above the ground that is much smaller than the radius of the Earth

R(earth) = 6.4x10^6

So my attemot at a solution
1) I've got that p = mass/volume so intergrating the expresion with respect to volume gives the total mass of the Earth r = v^(1/3).
then R(earth) >> r
but then i get stuck.

2) I've tried to divide the equation through by V but still that leaves me with
r(earth) >> r.

the problem is deailing with the much greater than part of r(earth) >> r, i don't know how to approach it.

thanks guys :)
 
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  • #2
No one even got a clue on how to solve this?
 
  • #3
What is the mass of the air that lies between a height r and a height r+dr?
 

1. What is the purpose of physics modelling in science?

The purpose of physics modelling is to create simplified representations of real-world physical systems in order to better understand their behavior and make predictions about their future states. It allows scientists to study complex phenomena, such as the motion of objects or the behavior of fluids, in a controlled and repeatable manner.

2. What are the key components of a physics model?

A physics model typically includes mathematical equations, physical laws and principles, and input parameters that describe the system being studied. It may also incorporate simplifications and assumptions in order to make the model more manageable and easier to analyze.

3. How do physicists validate their models?

Physicists validate their models by comparing the predictions of the model to real-world observations or experimental data. If the model accurately reflects the behavior of the system, it can be considered valid and useful for making predictions.

4. What are some common challenges in physics modelling?

Some common challenges in physics modelling include accurately representing the complexity of real-world systems, accounting for all relevant factors and variables, and balancing accuracy with simplicity. It can also be difficult to account for uncertainties and unexpected outcomes in a model.

5. How is physics modelling used in other fields of science?

Physics modelling is used in a wide range of fields, including engineering, biology, chemistry, and environmental science. It provides a framework for understanding and predicting the behavior of natural and man-made systems, and has practical applications in areas such as designing new technologies, predicting climate change, and studying the human body.

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