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What is the potential energy of the human body? 36 MJ $\simeq$ 8600 kcal. The basal metabolic state for a human is about 60 W. Let's assume (horrible) an immobile person dies after one week (604800 s) of starvation, he will have consumed 60 W * 604800 s = 36,288,000 J. Where does this energy come from? from the high energy chemical bonds of ...

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1.) You lose energy by doing work. The difintion of work by itself is the product of force and dislplacement(if the force is onstant) or else $\int_{}{}F dx$ for non constant forces.In case the case of doing a plank, you do zero work though you are resisting the force of gravity. So in terms of physics, you lose 0 energy even though you get tired. The reason ...

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Energy does not require force, as a moving object will have kinetic energy even if no force is acting on it. To give energy to an object is using work, so the second question is really asking if force requires work. The definition of work is the integral of the force function from the inital position to the final position. Even if there is a force, if the ...

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That's not quite how the brain works. Not a lot of mass actually moves, but the electrical impulses with which neurons communicate require the repetitive movement of electrical charge against differences in electrical potential, and that takes work. In fact, the human brain requires significant energy to do its job. Quoting from Appraising the brain's ...

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Ionizing radiation is radiation that is strong enough so that, when it hits an atom or molecule, will knock off electrons. This happens even if the target object doesn't have freely mobile electrons, which leaves free radicals and broken bonds, both of which are harmful to complex biological processes. There's no selection based on electron binding energy; ...

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The Earth has an average density of about 5500 kg/m^3. For a small planet, the density would be pretty similar throughout. Therefore the force of gravity you would experience on a planet with Earth density is: Your Mass * 5500 * 4/3pi * r^3 / r^2 * 6.6723 * 10^-11 This is equal to about 1.456 * 10^-6 * Your Mass * Radius of Small Planet. (I know, if you ...

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The problem is in your assumption that "we fall into open space" unless the planet is large enough. Even if there were no planet at all, we would not fall. In open space you just stay where you are - unless you are affected by some star or planet. In other words you will always drift slowly towards something or other. Now the earth's gravity is so large ...

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Lets just start with the cosmic velocity assuming you dont want to escape fully. $v \le \sqrt{\frac{2GM}{r}}$, where M is the mass of the planet and r is the distance to the center of Mass. We assume a spherical planet. We know the average density $\rho$ of our planet earth and since you will probably want to live on the new planet we will assume it has ...

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Because in the retina of human eyes there are light detector cells of two kinds: rods and cones. Cones "see" colors but are not very good with low brightness. Rods don't detect colors but are better than rods in low brightness situations. Thus at night cones don't function (they are for bright light) and we see only with rods which don't differentiate ...

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With my understanding, any color except black will reflect light, and a black color will absorb light without reflecting back out. So, at night, there won't be enough light to shine on anything to have a reflection. Then, your eyes won't see anything

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The heart only acts as a big dipole, when it is electrically active. ECG measures the potential difference between different places on the skin. These potential differences are created when different parts of the heart muscle are in dfferent stages of their action potential. For example, when the septum and the subendocardial myocytes are depolarized, but ...

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The definition of entropy can be found on Wikipedia. It's the integral of the reversible heat flow divided by the temperature at which the flow occurs. This has, at face value, nothing to do with order and disorder because there is no obvious way to even define structure in thermodynamics. One has to understand the link between thermodynamics and ...

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