Force per unit area.
5
votes
5answers
631 views
What would ACTUALLY happen to a person jettisoned into space?
[insert obligatory statement of my lack of knowledge in physics]
Alright, so we have all seen the movies where someone gets blasted out of the airlock on their starship, or their suit decompresses ...
2
votes
2answers
1k views
Balloons and lifting gases
Hydrogen is the lightest element, so it's cable of lifting the most weight in out atmosphere (probably not the best terminology there, but you get the picture)
Would hot hydrogen (in the same sense ...
1
vote
1answer
2k views
Pressure of sealed in liquid nitrogen
If you
take a container of great strength,
fill it to the brim with liquid nitrogen,
seal the container, and
heat it to room temperature.
What will the pressure be inside?
Bonus: The same with ...
3
votes
3answers
714 views
Define Pressure at A point. Why is it a Scalar?
I have a final exam tomorrow for fluid mechanics and I was just looking over the practice exam questions. They do not provide solutions. But pretty much I have to define pressure at a point and also ...
9
votes
4answers
2k views
Why can't CO2 mix back with the liquid after a soda bottle has been shaken?
If you shake a soda bottle before opening it, and then open it, you get the fizz.
That is the compressed CO2 releasing to the atmosphere which is at comparatively low pressure value.
Two questions ...
6
votes
2answers
148 views
Why water in the sink follow a curved path?
When you fill the sink with water and then allow the water to be drained, the water forms a vortex.. And then it starts to follow a curved path downwards by effects of gravity..
Why this phenomena ...
3
votes
2answers
644 views
How can sound waves propagate through air?
We know that the sound waves propagate through air, and it can't travel through vacuum. so the thing that help it doing that is the air's molecules pressure. So my question how can that happens? I ...
2
votes
2answers
31 views
Gas Circulation Using Pressure Difference
Dear all, see attached picture
Please, is it possible to have the gas recirculated from the gas phase to the liquid as described in the diagram assuming the gas is not soluble in the water.
These ...
1
vote
3answers
562 views
Maxiumum weight a buoy can float [closed]
I have a buoy that can hold 2943.02 cubic millimeters of non-pressurized air, I need and equation to work out the maximum weight that the buoy can float.
36
votes
11answers
4k views
How long a straw could Superman use?
To suck water through a straw, you create a partial vacuum in your lungs. Water rises through the straw until the pressure in the straw at the water level equals atmospheric pressure. This ...
8
votes
4answers
1k views
Water pressure in free fall
The increasing water pressure as you go deeper is generally explained in terms of the weight of the water column above the observation point pressing down. The question, then, is what would happen if ...
5
votes
1answer
318 views
Why is pressure in a liquid the same in all directions?
I'd like answers both in the more intuitive side an on the more precise side.
Thinking of water as "cubes" of water, for example, would allow pressure in the z axis to be independent of the y or x ...
6
votes
1answer
464 views
Ping-pong ball pontoon
Imagine a vertical pipe (both ends opened) in the water. Drop several ping-pong balls into pipe and cover them with a cylinder. When you have enough balls, the cylinder will float. Now start adding ...
4
votes
2answers
249 views
How to calculate the highest theoretical artificial hill?
The biggest peak in the world is Mount Everest.
Imagine someone starting to make an artificial hill (like pyramide) from soil (earth).
So, when starting with an 200x200 Km base area, with 45degree ...
4
votes
0answers
775 views
Inflating a balloon (expansion resistance)
I am doing a quick calculation on how to calculate the pressure needed to inflate a perfectly spherical balloon to a certain volume, however I have difficulties with the fact that the balloon (rubber) ...
4
votes
2answers
712 views
If I put a ping pong ball in a vacuum, would it pop?
If I put a ping pong ball in a vacuum, would it pop? If so, at what point would it happen? Any standard table ping pong ball is acceptable.
3
votes
1answer
118 views
Why does the bubbling of a soda bottle pulsate?
If I take a bottle of carbonated water and open the cap slightly to allow the gas to escape, there will be a sudden rush of bubbles foaming to the top of the liquid for a few seconds, then a partial ...
8
votes
5answers
2k views
If I take a bottle of air into space, and open it, where does it go?
It seems to me that space doesn't have any/much air, and if my bottle is full of air, when I open it, where does the air go?
3
votes
2answers
999 views
How deep in the ocean can a ping-pong ball go before it collapses due to pressure?
Stimulated by the calculation showing that a ping-pong ball does not pop in vacuum, I'm driven to ask how deep in the ocean a ping-pong ball can be brought before it collapses due to pressure.
This ...
3
votes
3answers
1k views
What is the relation of sound propagation to air pressure?
Hi there i am wondering, air is making sound propagate. So in vacuum there is no sound. but what is the relation of pressure to sound volume? is it linear?
if i have a source of sound and lets say i ...
1
vote
2answers
91 views
Amount of material required for a pressure tank
I read the answer for the question Why is a hot air balloon “stiff”? and thought something sounded ridiculous. My engineering requirement is that the walls be strong enough. Here $T$ will be the ...
0
votes
1answer
1k views
How much work is needed to compress a certain volume of gas?
I want to know the formula (and what does the symbols stand for) for how much work is needed to compress a certain volume of gas?
0
votes
2answers
350 views
What is the physical or mathematical meaning of the Gibbs-Duhem equation?
The Gibbs-Duhem equation states
$$0~=~SdT-VdP+\sum(N_i d\mu_i),$$
where $\mu$ is the chemical potential. Does it have any mathematical (about intensive parameters) or physical meaning?
-2
votes
2answers
156 views
Why does the higher pressure of air underneath an aeroplane wing keep it flying?
With aeroplane flight, the wings are shaped so that the air that goes over the top of the wing has to travel faster than the air that goes below the wing. This means that the air below the wing has ...
