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3

The equation you need is that force is equal to the rate of change of momentum. The force is the weight of the rocket, $Mg$, and the rate of change of momentum is the mass ejected from the exhaust per second multiplied by the exhaust velocity. $$Mg = v\frac{dm}{dt}$$ So choose your exhaust velocity $v$, and you can work out the required $dm/dt$. The ...

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As DanielSank said, I cannot say anything quantitative about the question without a diagram. That being said, your formula, in general, is correct if the topology of the circuit is symmetric. Without any details about how mechanical energy is coupled to the circuit, I can only guess the general reason for the apparent non-conservation of energy. This ...

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Are you sure you mean the internal resistance "r"? The internal resistance typically can not be adjusted, often this question is phrased in terms of the load resistance "R". The power dissipated in the external load is: $$P=\frac{V^2 R}{(r+R)^2}\;,$$ which you need to maximize. If you maximize with respect to R, you find R=r... If you maximize with ...

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You use the term "Power" but what you are asking about is "energy" or "work done". Power is an instantaneous measure of the rate of doing work which is the same as the rate of using or supplying energy. The standard relationship at constant Velocity V over a distance D in time T is: D = V x T which can be rearranged as .... V = D/T or .... T = D / V Two ...

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http://www.launc.tased.edu.au/online/sciences/PhysSci/done/kinetics/wep/Work.htm The above link talks about WORK, ENERGY and POWER. Does this basic concept of physics applies all only to OBJECT and not to Human doing the work or applying power and using its own energy? Just confused here and I think I was wrong in linking with Human energy. If I pushed an ...

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Assuming your question is about the concept of energy in physics: The muscle actually uses chemical energy. How this works in detail is not a physics but a biology question. The chemical reaction will create heat and cause your muscle to contract. Consequently, your body loses chemical energy, that's why you have to eat, drink and breath, to keep these ...

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Usually nuclear rockets have lower thrust than chemical rockets, in a nuclear rocket you are trying to get the heat from the reactor into the propellant, which means a lower temperature. In a chemical rocket you have all the heat in the propellant, and try to avoid getting it anywhere else. Nuclear rockets make up for this deficiency by using a very light ...

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Building a nuclear reactor is very large-scale investment, and as thorium reactors are unproven, and there is already a large infrastructure in place for the uranium fuel cycle (mining, purification, enrichment, rod fabrication, etc...) a uranium reactor is considered a safer investment.

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Significant (and practical) energy capture - probobly not. Indirect energy capture, like warming water during the day time and then using that water to warm your home at night - sure. Pretty sure that's already done in a few places. But electricity generation from day to night time temperatures - that's hard. The most practical way (that I can think ...

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To get a negative number for power, the time averaged product of voltage and current must have been negative. Now if you are properly sampling voltage and current at the same time, for the transformer you are measuring (where power is obviously being dissipated in the transformer, not generated by it), you would expect at low frequencies to have the voltage ...

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