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stevmg
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To maintain a 550 lb mass in the air not touching the ground at sea level (radius of Earth is 4000 miles), what is the expenditure of energy required given perfect efficiency of the process?
You're describing a mass sitting on a table or hanging by a chain. It doesn't require any more energy than if the object were sitting on the ground, which is to say none at all.stevmg said:To maintain a 550 lb mass in the air not touching the ground at sea level (radius of Earth is 4000 miles), what is the expenditure of energy required given perfect efficiency of the process?
Why do you say that? Because you don't like the answer, or because you think it is wrong?stevmg said:Still, no answers posted. Only vague generalities.
Your question is too vague to be answered except in the case where the object is suspended from a rigid object (tree, crane, etc). In that case the answer is zero, as stated in every response so far. If you mean any other case then you need to provide details of the support mechanism.stevmg said:Still, no answers posted. Only vague generalities.
Don't want to start a "fight."Ibix said:Your question is too vague to be answered except in the case where the object is suspended from a rigid object (tree, crane, etc). In that case the answer is zero, as stated in every response so far. If you mean any other case then you need to provide details of the support mechanism.
Is there any way to convert horsepower into pounds thrust?stevmg said:Don't want to start a "fight."
It will if it's hanging from a bridge. What are you hanging it from? Rocket? Helicopter? Hot air balloon?stevmg said:BUT it won't stay up on its own.
No, because they are measuring different things. Pounds of thrust is a measure of the force being applied to something, while horsepower is a measure of how much energy is being expended per unit time. If I hang a 100lb weight from a chain, the chain is applying 100 pounds thrust to the weight to balance out the force of gravity while burning no energy and producing zero horsepower as it just sits there. On the other hand, if I try supporting the weight using a rocket engine that generates 100 pounds of upwards force, then much energy will be spent pushing hot exhaust gases around. But the pounds of force is the same either way.stevmg said:Is there any way to convert horsepower into pounds thrust?
Not in a general way, but for certain dynamic propulsion devices such as fans, you can calculate the input power required to get a certain thrust. What you find if you plug in different specs, is that the input power for a fan does indeed drop asymptotically to zero as the rotor diameter increases.stevmg said:Is there any way to convert horsepower into pounds thrust?
Nugatory said:No, because they are measuring different things. Pounds of thrust is a measure of the force being applied to something, while horsepower is a measure of how much energy is being expended per unit time. If I hang a 100lb weight from a chain, the chain is applying 100 pounds thrust to the weight to balance out the force of gravity while burning no energy and producing zero horsepower as it just sits there. On the other hand, if I try supporting the weight using a rocket engine that generates 100 pounds of upwards force, then much energy will be spent pushing hot exhaust gases around. But the pounds of force is the same either way.
No matter how much or how little force I apply to something, no horsepower at all is required if it's not moving. That's why the answer to your original question, supplied by many posters already, is "zero".
Not a waste of time, it's just that your approach was a little off-putting in how short your first response was. But we're glad you figured it out.stevmg said:Thank you, Nugatory
I think "I've got it."
It has taken me forty years to figure this out. Sorry for wasting everybody's time.
The amount of energy required to levitate a 550 lb mass at sea level would depend on the method used to achieve levitation. In general, it would require a significant amount of energy as it involves counteracting the force of gravity on the mass.
The energy required for levitation would be affected by several factors such as the weight and size of the mass, the method of levitation, the altitude at which the levitation is taking place, and the surrounding environment.
Yes, the energy requirement for levitation can be reduced by using more efficient and advanced methods such as magnetic levitation or utilizing aerodynamic forces. Additionally, reducing the weight of the mass would also decrease the energy needed for levitation.
No, it is not currently possible to levitate a 550 lb mass at sea level without using any external energy. The force of gravity would always counteract any attempt to achieve levitation, and it would require some form of energy to overcome this force.
The energy requirement for levitation would increase at higher altitudes due to the decrease in air density. This would result in less resistance against the force of gravity, making it more difficult to achieve levitation without using additional energy.