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#21
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Does the Weight of an Airplane and Contents Change?
The weight lost from perspiration and the passengers burning calories
is insignificant. Consider that a plane burns a few thousand pounds of fuel per hour, then even if you had each person managing to burn a pound of energy sustaining themselves on the flight (a generous guesstimate) on a 747 you'd come in ~400 lbs less at landing than takeoff. No biggie. And that would assume the pound used to sustain themselves left the plane. After all, if you lose a pound, it doesn't disappear, it goes someplace. I'm not talking about people ****ting here. When you sit at your computer, your body burns calories generating heat, speaking, moving around, digesting food, etc. The mass of food you ate on the plane or before boarding is converted to heat, sound, kinetic energy. The fact that people sit on a plane more or less emphasizes that this loss of energy, and the mass used to create it, is tiny, and therefore negligible. This is not a nuclear reaction, the energy is created by the breakdown of chemical bonds in the food. No mass is lost at all. |
#22
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Does the Weight of an Airplane and Contents Change?
mtravelkay schrieb:
Well, the plane would weigh less because the fuel would have been burnt and byproducts of this would have left the plane. As far as the food, etc refer to the Law of Conservation of Mass: Matter can not be created or destroyed. So, unless it finds a way off the aircraft, it would still be on the aircraft. Already heard of carbonic dioxide and water? Regards, ULF |
#23
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Does the Weight of an Airplane and Contents Change?
freeda wrote:
The weight lost from perspiration and the passengers burning calories is insignificant. Consider that a plane burns a few thousand pounds of fuel per hour, then even if you had each person managing to burn a pound of energy sustaining themselves on the flight (a generous guesstimate) on a 747 you'd come in ~400 lbs less at landing than takeoff. No biggie. And that would assume the pound used to sustain themselves left the plane. After all, if you lose a pound, it doesn't disappear, it goes someplace. I'm not talking about people ****ting here. When you sit at your computer, your body burns calories generating heat, speaking, moving around, digesting food, etc. The mass of food you ate on the plane or before boarding is converted to heat, sound, kinetic energy. The fact that people sit on a plane more or less emphasizes that this loss of energy, and the mass used to create it, is tiny, and therefore negligible. This is not a nuclear reaction, the energy is created by the breakdown of chemical bonds in the food. No mass is lost at all. Are you saying, that when you excercise on a daily basis to lose weight, that any weight you shed must come off in sweat and waste only? |
#24
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Does the Weight of an Airplane and Contents Change?
"enderremove @telus.net" "enderremove wrote in message news:HN_7c.2517$Ct5.1254@edtnps89... freeda wrote: The weight lost from perspiration and the passengers burning calories is insignificant. Consider that a plane burns a few thousand pounds of fuel per hour, then even if you had each person managing to burn a pound of energy sustaining themselves on the flight (a generous guesstimate) on a 747 you'd come in ~400 lbs less at landing than takeoff. No biggie. And that would assume the pound used to sustain themselves left the plane. After all, if you lose a pound, it doesn't disappear, it goes someplace. I'm not talking about people ****ting here. When you sit at your computer, your body burns calories generating heat, speaking, moving around, digesting food, etc. The mass of food you ate on the plane or before boarding is converted to heat, sound, kinetic energy. The fact that people sit on a plane more or less emphasizes that this loss of energy, and the mass used to create it, is tiny, and therefore negligible. This is not a nuclear reaction, the energy is created by the breakdown of chemical bonds in the food. No mass is lost at all. Are you saying, that when you excercise on a daily basis to lose weight, that any weight you shed must come off in sweat and waste only? You are 'burning off fat' Fat is only stored energy, and this is broken down into something you ****/****/sweat. |
#25
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Does the Weight of an Airplane and Contents Change?
You are 'burning off fat' Fat is only stored energy, and this is broken down into something you ****/****/sweat. You're right (I think) and I feel like an idiot. I should go take a chemistry class I think |
#26
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Does the Weight of an Airplane and Contents Change?
You are 'burning off fat' Fat is only stored energy, and this is broken
down into something you ****/****/sweat. You're right (I think) and I feel like an idiot. I should go take a chemistry class I think You have to excuse me, I'm a Physics graduate (well 10 years ago) so I get a little anal about these things... |
#27
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Does the Weight of an Airplane and Contents Change?
"Miss L. Toe" wrote:
But going back to an offshoot from the OP's original question, how much the weight of the aircraft be reduced at 30,000 feet due to the reduction in gravity ? If you are discussing weight (as opposed to mass), then the weight of a pressurized aircraft actually increases at altitude. On the ground, air pressure being equal, the air inside the aircraft doesn't weight any more than the air that would otherwise occupy the same volume if the aircraft were not there. But at altitude, the air inside the cabin weighs more than the air that would occupy the same volume. On the former CP web site, they stated that this difference was in the order of one tonne for a 747-400. In terms of gravity, gravity changes in relation to the distance from the centre of the gravity generating mass. Earth has a radius of about 6366km. Adding 10km for the plane's altitude changes the force of gravity very little. |
#28
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Does the Weight of an Airplane and Contents Change?
There is no jettisoning of toilet waste on an airliner, not intentionally,
anyway. Could you imagine what kind of nasty ice block that would make?? "A Mate" wrote in message ... E=mc2 - refers to energy creation and destruction of matter - as in a nuclear or thermo-nuclear reaction. Nothing to do with the energy transformations which occur in the human body!! The aircraft would weigh exactly what it did on take-off MINUS the weight of water lost in air exchange, fuel burnt and waste matter jettisoned through the toilet and waste water systems. "nobody" wrote in message ... Alan Bell wrote: after we eat, the same as when the plane took off? And what about two hours after we eat? When nature takes it course, is the aggregate weight still the same? Overall, you sweat or exhale a lot of the water contents of the food you eat/drink, and that humidity is dumped overboard as the air is replaced in the cabin. The E = MC2 aspect would probably be so small that it wouldn't matter with regards to mass converted to energy by muscles. |
#29
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Does the Weight of an Airplane and Contents Change?
"Alan Bell" wrote in message news:Z_N7c.61093$1p.1013582@attbi_s54... Yes, I understand that. But the expenditure of jet fuel wasn't the thrust of my question and I take responsibility for writing my question wrong. I should have written: "Is the combined weight of the people, the food, the food containers, the waste facilities and the air we breathe -- I'm trying to think of everything related to the passengers, the food and its consumption -- constant over the course of the flight? To a very close first approximation, yes. The only significant change in the weight (or mass) of the aircraft comes through the consumption of fuel. Bob M. |
#30
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Does the Weight of an Airplane and Contents Change?
"freeda" wrote in message ... Is excrement not jettisoned overboard? We have all heard stories of frozen turds crashing through roofs. No, never intentionally. Most of these stories are apocryphal; the few with legitimate roots originate with failure of the system, specifically the valve that permits the waste to be pumped from the aircraft after the flight. Bob M. |
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