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7m
comment Analytical solution of transient barometric formula for fluid in one dimension
Ah, I see what you mean. Did you actually calculate the steady state density distribution? This would be a first step. Then, you assume $d\rho/dx=0$ at th boundaries, but that is not what the exponential profile statisfies? Or am I missing something here?
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reviewed Close Quasicrystals - Projections from higher dimensional regular crystals
47m
comment Analytical solution of transient barometric formula for fluid in one dimension
What do you want to solve exactly? As you say everthing is at rest and thus $u=0$.
4h
reviewed Close Fourier Transform of Poisson Equation
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awarded  Guru
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comment Which ball touches the ground first?
Your answer is not complete, as $a$ also depends on the velocity. If the heavier object accelerates quicker, the velocity is higher, and thus acceleration lower. I think if you want to claim that, you will need a further analysis.
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reviewed Reject suggested edit on How do I figure out the momentum of a water balloon when it reaches the person I am throwing it at?
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reviewed Reopen How to compute observables from the boson field operator?
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reviewed Close How much inductance and capacitance generate in copper strip?
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comment Which ball touches the ground first?
@Awal Notify me there, and I will be there when I have time
12h
comment Which ball touches the ground first?
@Awal Well, I would be interested in an order of magnitude analysis. Or maybe even an analysis of the terminal velocity in absence of air friction. You might easily get into relativistic regimes.
12h
comment Which ball touches the ground first?
@Awal Did you estimate how large this force is compared to typical friction forced by the surrounding fluid?
12h
comment Which ball touches the ground first?
@Saffron I don't agree. It is obvious that at any stage the heavy ball will fall faster (for $t>0$), due to the imbalance in forces. I don't think adding differential equations for transient terms really adds anything in the concept of air friction. Is you think it is important, feel free to add an answer where you do these derivations and show a closed form solution for the balls trajectory. Conclusions will be the same.
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reviewed No Action Needed Question on using Leibniz formula to derive thin-film equation from Navier-Stokes
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comment Calculate water flow rate through orifice
@Jim I agree, but Eric could have shown a lot more of what he actually did already, as apparently he has more info than he shares.
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reviewed Leave Open Calculate water flow rate through orifice
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awarded  Good Answer
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reviewed Reject suggested edit on With what velocity should an $\alpha$ particle travel towards a Cu nucleus so as to arrive at a distance of $10^{-13}$ m?
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reviewed Approve suggested edit on Expanding a ket in the position basis?
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comment Which ball touches the ground first?
@FlipFlapFlop Maybe it is better to ask that as a separate question :)