Recent content by edanzig

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    Internal Energy: 10 Moles Helium & Oxygen at 100K

    "What is the internal energy of 10 moles of helium at 100 K?" The same question is asked about 10 moles of oxygen. I'm going to guess PV=nRT which would give 8,314 J as the PV value. Because (at least in chemistry this is true) delta H = delat E +/- work and work = PV, so PV would somehow...
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    Solve Air Pressure Problem: 500m Skyscraper, 1.3 kg/m3

    1 bar in Pa is approx is 100,000. The difference is 6370. Therefore the answer is .93 bar. (thanks) Just not sure when you say that rho*g*h gives pressure and not force, the units sum to "N" and not "N/m^2."
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    Solve Air Pressure Problem: 500m Skyscraper, 1.3 kg/m3

    The question asks; "Assuming that the density of air is a constant 1.3 kg/m3 and that the air pressure is 1 bar, what is the pressure at the top of a 500 meter high skyscraper?" I'm having trouble setting something up but here is what I do have; Regarding liquids we know that F =...
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    Calculating Efficiency of an Engine with Moving Piston

    A question is being asked about a combustion chamber that has a moving piston; "an engine." "Which expression expresses the efficiency of the engine?" The answer given is: (Pressure(from burning))(Volume)/(moles)(delta H) While this looks some thing like PV = nRT, I don't fully understand...
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    Why Does a Bicycle Wheel's Angular Momentum Point West When Traveling North?

    My mistake. I know nothing of this topic, I should have looked before asking...
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    Why Does a Bicycle Wheel's Angular Momentum Point West When Traveling North?

    A bicycle is traveling North. The direction of the angular momentum vector of it's front wheel is? I chose "North." The answer is West. Why? thanks
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    Net Force Homework: Direction of Net Force

    Homework Statement I don't have a picture of this situation so I will do my best to describe it in words. If we have a box that's "swinging" in a circular motion at the end of a string, but at the same time the box is experiencing a frictional force due to it's brushing against another...
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