# Tag Info

### Why the pressure of atmosphere doesn't crush you when you e.g. walk outside?

Pressure acts in all directions. it does not care about direction. pressure is a property of the fluid itself. but the way you CALCULATE it is to find the 'weight of the air above'. this does not mean ...
• 111

### If you decreased the mass of a planet, but kept the mass of the atmosphere the same, would the air density decrease?

In an isothermal atmosphere, the density is given approximately by $$\rho = \rho_0\exp(-\mu gh/k_BT)\ ,$$ where $\mu$ is the mean mass of a particle, $h$ is the height above ground level and $g$ is ...
• 113k
1 vote

### If you decreased the mass of a planet, but kept the mass of the atmosphere the same, would the air density decrease?

Yes the air density would decrease. The density is proportinal to $e^{-g*h/T}$ where g is the local force of gravity h is the height and T is the tenperature. Lower gravity gives lower pressure and ...
• 1,713
Accepted

### Would a straw work in a completely sealed container?

No. If the air can't get in the container in any way other than the straw than you won't get any water. A tiny amount of water may go up the straw a bit but it wouldn't be a reasonable amount to drink....

### Does dusk really remain for a shorter period of time at the equator?

I get the sense that the OP might have been wondering about what seems like a riddle: if people near the equator are moving faster (due to the earth's rotational speed), shouldn't they "go ...
• 101
In the range of pressures we have in the troposphere the gas law holds perfectly, but we have to interprete it in a proper way. Lest's solve for P the equation of the gas law: $$P=\frac{n} {V}RT$$ ...