# Tag Info

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Without knowing a lot more about the details of the entire system, we can't say exactly what the difference will be between the AC1+AC2 case and the AC2-only case. However, there are a few things we can work out from simple energy balance. In the following, I'm considering the air as an ideal gas with a fixed specific heat capacity at constant pressure ...

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If you're objective is to cool down the office, and you have a machine blowing air into the office which is warmer than the current (indoor) ambient temp. then I would by all means turn the damned thing off! air conditioners are heat pumps, just like a fridge. They take in the ambient air, pass it over a cool surface (to absorb the energy from the air) and ...

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I describe this in my book "Guesstimation 2.0" (Princeton University Press, 2012). The work done by the expanding shock wave is pressure times change in volume. The change in volume is as described by the previous answer: 2.5 m * 2pi * (16 km)^2. Fermi could feel the extra pressure due to the explosion, we can only estimate it. The extra force on his ...

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Measure the "thickness" of the fan blade. That is, the distance from the front to back of the twist in the blade. Now find how many times per second the blade rotates. Multiply that blade thickness (distance) by the number of times per second the blade moves through that position. It will give you an upper limit on air velocity.

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Your drawing shows an empty box . If it is at room temperature and not air tight the inside and outside air pressure are in equilibrium, the arrows balance against the rigidity of the wallss If the box is air tight and the inside is a vacuum then it will be crushed. Nobody makes vacuum tubes from polysterine. Why we can have vacuum tubes ( incuding ...

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It looks like you don't take into account elastic forces in the rigid cube. The pressure on the cube's faces will tend to bend them inwards, the force will be passed to the ribs, so the faces and the ribs will get compressed, and they will resist compression. Perhaps it is easier to understand what happens if you consider an evacuated spherical shell, rather ...

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I am reading your question as wondering why the total force on the (smaller) inside surface area of the cube is not crushed by the (larger) outside surface area. Perhaps exaggerating this will make it a bit clearer. Yes the total force on the outside is larger, but much of that force does not reach the interior of the cube. If you imagine the force from ...

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You can use your old friend $PV^\gamma=k$ for the expansion. Imagine putting a divider sheet across the tank, with $0.75m_1$ on the side away from the outlet and $0.25m_1$ on the side toward the outlet. As the gas is released, the sheet moves until it is against the wall with the outlet. If the divider is massless, the pressure is the same on both sides, ...

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As the humidity of the air increases, its density decreases, so the fan blades will have an easier time passing through the air. I doubt the fan blades move muchy faster, because they are synched to the motor, but perhaps the decrease in force to pass through the air leads to a louder fan. What have you observed?

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In the short term, the sloshing of the water as you not-completely-cleanly let go of the bottle will be the dominant effect. In the long term, since you're ignoring air resistance, and if we assume the bottle isn't spinning in any way, then surface tension will dominate. Different material interfaces have different energies, and absent other forces those ...

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A liquid / gas mixture in an enclosed vessel in a zero-g environment can be quite weird. Given enough time, the contents of the tank eventually become an ethereal mix of blobs of liquid, bubbles of gas, and foam. This creates a significant design challenge for liquid fuel tanks intended for use in space. One solution is to use a bladder to separate the ...

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The environment in a free-falling object is the same as one without a gravitational field (neglecting gradients in the gravitational field, i.e. tidal forces). So, before you drop the bottle, gravity is holding the water at the bottom and creating a slight air pressure gradient between the top and the surface of the water, and a water pressure gradient ...

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If you drop a bottle without any residual motion (that is, it is not spinning etc) then everything inside that bottle will be in "free fall". The air and the water will attempt to fall at the same rate. There is a nice video of what happens to water when it "spills" in the International Space Station: it becomes a "blob" because of the surface tension. Add ...

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I think nothing. Example #1: Calculate the rms speed of an oxygen gas molecule, O2, at 31.0 °C Solution: $v=\sqrt{\frac{3RT}{M}}=\sqrt{\frac{3 \times 8.31447 \times 304.0}{0.0319988}}=486.8 m/s$ That is pretty high average speed of oxygen molecules. The acceleration of the bottle does not change it much at beginning. The direction of molecules motion is ...

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