New answers tagged

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We know the lift force is perpendicular to the airplane. Roll angle (about longitudinal axis) is such that the lift force vertical component equals the weight of the plane $mg$and the lateral component equals the centrifugal force requirement $ma$. If the plane tilts, then the lift force has three components: vertical, lateral and longitudinal. If pitch ...


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I'd rather guess it is effect of some external factor. Maybe wind around the tram station is typical for some certain direction, or something like so.


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It's difficult to give a definite answer based on the description of the phenomenon (I've never encountered it where I live), so here are a few hypotheses that you might test. If the air displacement is directly caused by the acceleration and deceleration, you would expect the air to flow backward during acceleration and forward during deceleration. ...


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If the pipe is cylindrical, there is no equilibrium height. All the air that goes in at the bottom must come out at the top, so the force balance will not depend on the height of the ball. In a ball flow meter (rotameter), the pipe is slightly conical, so that the gap between the ball and the pipe increases as the ball rises. If you want a very coarse ...


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The air flow around the car creates a vortex. There is an image of the air flow around a car: which was used by this earlier answer - that rotating air behind the car is what spins the wheels of the bike.


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The paper by Yusuf Billah and Robert Scanlan (cited in the wikipedia article on the Tacoma Narrows Bridge 1940) distinguishes between resonance as a response to a driving force and what the authors call "self-excitation" or "negative damping." They demonstrate that the Karman Vortex Street (which occurs at the trailing edge of the deck) was not the cause of ...


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This is hard to answer quantitively. A train in open air pushes air out of the way, and sucks air in behind it. Some air is dragged along with the train. Mostly air moves near the train. In a New York subway, you can feel a strong breeze before the train arrives. The tunnel diameter isn't that much larger than the train, so the train acts something like ...


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Chaos is typically phrased as a sensitivity to perturbation in initial conditions (amongst other important things things). You can have a statistical distribution describing the final destination of leaves in general, when the path taken by any individual leaf is deemed chaotic. As an example, consider common strange attractors. Its easy to see that there ...


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It depends on your exact definition of chaos: We certainly have a strong sensitivity to initial conditions (butterfly effect), which is the one property of chaos everybody seems to agree upon. We do not have topological mixing. The falling to the ground is only a short-lived transient compared to the non-chaotic lying on the ground. So, at most, we have a ...


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Yes. With the qualification that chaos describes the behaviour of an ideal (continuous?) mathematical model, whereas leaves and the air through which they fall are real, I think it is a chaotic system. Leaves falling from the same place but with a small change in orientation can land in very different places, and intermediate orientations do not necessarily ...


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This is something I have looked into a great deal, having an interest in model rotorcraft, including single bladed machines. As with nearly all things related to aviation, and engineering in general, there is no optimum or best answer to number of blades. It is all about trading off cost, performance, reliability, weight, etc. etc. etc. "Best" will depend ...


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It may be 5 years on from the original question, but it's a shame to have only a single accepted answer, which is just plain wrong. Though it's true, that the human body has a "natural intuition for physics", this is only within a pretty wide margin of error (which gets narrower with practice in spear-throwing). It is not a flick of the wrist, which makes ...


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Bernouli does not explain wing lift. You can measure an older light plane with a "plank" wing, factor in the wing area, distance over the upper and lower surfaces, cruise speed, and air density, and come up with a total lift figure of about 25% of the aircraft weight. Bernouli equations were published in an aviation text decades ago and the error propagated ...


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The other way around is more intuitive; if the pressure is lower on the right, the fluid would feel a net positive force in that direction and accelerate toward right. hence it will have higher velocity there. So, lower pressure will result in higher velocity. you can rephrase the above in a way that it sounds as what you may like but is not scientifically ...


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1)For net wt 100kg to be lifted in air ,lift has to be greater than equal to 100kg. 2)To produce minimum of 100kg lift ,it depends upon shape,size,weight,angle of attack of wing and lastly speed /velocity of wing/plane.Further velocity depends upon thrust ,total mass and drag(shape of flying machine). In simple words only Forward thrust,total weight and ...



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