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Hunter1234
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I understand that this will vary from human to human, but how much weight is exerted, in total, on the average adult human body. It would be very much appreciated if the calculations can be shown. Thanks!
I suspect that you are looking for an answer to a question that has been given you or to settle an argument (?). The essence of what's going on is not really explainable in the terms of your question. It's really important to distinguish between Force (eg. weight) and Pressure (e.g. Newtons per square metre))Hunter1234 said:how much weight is exerted, in total, on the average adult human body.
I guess what you really want to know is the total atmospheric force exerted on the human body. The average human body surface area is 1.73 m2 and the standard atmospheric pressure is 101,325 N/m2. Hence the total atmospheric force exerted on the average human body would be 1.73 m2 x 101,325 N/m2 = 175,300 N (approx.).Hunter1234 said:I understand that this will vary from human to human, but how much weight is exerted, in total, on the average adult human body. It would be very much appreciated if the calculations can be shown. Thanks!
I was going to give a spherical cow answer.NotBillNye said:The average human body surface area is 1.73 m2
This is not correct, because the pressure force on a surface is normal to the surface, and, these normal forces on the body must be added vectorially. If you do this correctly, as was done by @mfig, you get the answer he gave.NotBillNye said:I guess what you really want to know is the total atmospheric force exerted on the human body. The average human body surface area is 1.73 m2 and the standard atmospheric pressure is 101,325 N/m2. Hence the total atmospheric force exerted on the average human body would be 1.73 m2 x 101,325 N/m2 = 175,300 N (approx.).
Assuming standard gravitational acceleration as 9.80665 m/s2, this would be equivalent to 175,300/9.80665 kgf = 17,900 kgf.
That's a lot of force acting on the body but it's all counterbalanced by the internal pressure of the body and so you won't feel it at all. Hope this is the real answer you're looking for.
Sorry, have to disagree with you. Don't forget, the atmospheric pressure acts upwards as well via all the downward facing surfaces and the NET force would be zero. However, the pressures at the top of the body are slightly lower than at the bottom due to the weight of the air resulting in a small upward force (0.9N) as calculated by sophiecentaur.Chestermiller said:This is not correct, because the pressure force on a surface is normal to the surface, and, these normal forces on the body must be added vectorially. If you do this correctly, as was done by @mfig, you get the answer he gave.
I respectfully disagree. The forces have to be added vectorially, in my humble judgment. I guess we'll just have to agree to disagree.NotBillNye said:Sorry, have to disagree with you. Don't forget, the atmospheric pressure acts upwards as well via all the downward facing surfaces and the NET force would be zero. However, the pressures at the top of the body are slightly lower than at the bottom due to the weight of the air resulting in a small upward force (0.9N) as calculated by sophiecentaur.
But I suspect that Hunter1234 is more interested in the total force that would be crushing the human body if it had been hollow and filled with nothing, ie a vacuum, akin to the submarine deep under the ocean. That was what I was trying to calculate for him.
So I guess the answer really depends on what Hunter1234 is actually asking.
Don't forget, I'm not Bill Nye.
I suspect that you are right about what Hunter 'thinks' he wants to know. But the Force is really of no consequence unless we want to know about bouyancy. The effects of pressure on the human body are not so much Mechanical but Chemical. A human can 'breathe' air in and out at more or less any ambient pressure. The problem arises when the partial pressures of gases in the air (and also within the body) are 'inappropriate' for respiration and the rates of gaseous exchange do not sustain life. (That's why saturation divers use special mixes of gases.)NotBillNye said:But I suspect that Hunter1234 is more interested in the total force that would be crushing the human body if it had been hollow and filled with nothing, ie a vacuum, akin to the submarine deep under the ocean. That was what I was trying to calculate for him.
The lungs have a lot of surface area. Why not count that? Since the question is nonsensical, the answer should be as well.NotBillNye said:I guess what you really want to know is the total atmospheric force exerted on the human body. The average human body surface area is 1.73 m2 and the standard atmospheric pressure is 101,325 N/m2. Hence the total atmospheric force exerted on the average human body would be 1.73 m2 x 101,325 N/m2 = 175,300 N (approx.).
Assuming standard gravitational acceleration as 9.80665 m/s2, this would be equivalent to 175,300/9.80665 kgf = 17,900 kgf.
That's a lot of force acting on the body but it's all counterbalanced by the internal pressure of the body and so you won't feel it at all. Hope this is the real answer you're looking for.
If you squeeze an object between your hands, do you add the 10N from the left hand with the 10N from the right hand to get 20N of total force?NotBillNye said:But I suspect that Hunter1234 is more interested in the total force
Chemical or Thermal effects would be felt first. Secondly, the different pressure could be 'noticeable' but I doubt it.ras said:Now what would this be for the same human who (unwisely) stepped out of his space capsule unprepared on the surface of Venus?
Atmospheric Pressureforce exerted by the weight of the airHunter1234 said:I understand that this will vary from human to human, but how much weight is exerted, in total, on the average adult human body. It would be very much appreciated if the calculations can be shown. Thanks!
In aviation and television weather reports, pressure is given in inches of mercury ("Hg), while meteorologists use millibars (mb), the unit of pressure found on weather maps. |
I don't see what's the problem with that really. Chestermiller and the others are still around and can answer if they find the new reply interesting. The nice thing with electronic threads is that there is no paper yellowed out, no ink worn out, the thread appears as good as new.russ_watters said:This thread is 5 years old...
But the atmosphere is much the same.russ_watters said:This thread is 5 years old...
Atmospheric pressure is typically measured using a barometer, which measures the force exerted by the weight of the air above it. The most commonly used unit for atmospheric pressure is the pascal (Pa), but it can also be measured in other units such as millibars (mb) or inches of mercury (inHg).
The average atmospheric pressure at sea level is 1013.25 hPa or 14.7 psi. This is the amount of pressure that is exerted on the human body when standing at sea level.
Atmospheric pressure affects the human body in various ways. At high altitudes, where atmospheric pressure is lower, the body may experience symptoms such as shortness of breath and fatigue due to the decreased amount of oxygen in the air. At deeper depths, where atmospheric pressure is higher, the body may experience the effects of increased pressure, such as nitrogen narcosis and decompression sickness in scuba divers.
The human body is capable of withstanding a wide range of atmospheric pressures. However, extreme changes in pressure, such as sudden increases or decreases, can be dangerous and even fatal. The body is able to adapt to gradual changes in pressure, such as those experienced during airplane flights or scuba diving, but it may not be able to withstand sudden changes in pressure.
Atmospheric pressure decreases with increasing altitude. This is because there is less air above the body to exert pressure. For every 1000 meters increase in altitude, atmospheric pressure decreases by about 11%.