Recent content by Originaltitle

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    Calculate Percent Yield Questions: NaNO3 in Impure Substance (URGENT)

    % yield questions (URGENT) Homework Statement We have 3 equations: 1.64 g of an impure NaNO3-containing substance is reacted with Devarda's alloy. The amount of NH3 got from this reaction is reacted with 25cm3 1.00 moldm-3 H2SO4. The H2SO4 left over is reacted with 16.2 cm3 2.00 moldm-3 NaOH...
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    Particles undergo no disturbance at an antinode?

    Particles undergo no disturbance at an antinode? I thought antinodes were points of maximum displacement?
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    Torque (of a couple) and centre of gravity MCQ

    Homework Statement Homework Equations I know torque of a couple = One of the forces x the distance between the 2 forces. The Attempt at a Solution I don't know how to approach this blasted problem. Any help would be very much appreciated.
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    Solving Force and Motion Problems with the SUVAT Equations

    That is if we assume that they meet halfway - nowhere in the question does it say they meet halfway. If they do meet halfway, the g.p.e. of the man = 800*100*9=720000J and the barrel's loss in g.p.e. = 1200*100*9=1080000J. If we say the loss in g.p.e. = gain in k.e., then 1080000 = 0.5*80*v^2...
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    Solving Force and Motion Problems with the SUVAT Equations

    Could you be more elaborate, please? I mean, if I were to use conservation of energy, I'd need to use W.D.=Fx, K.E.=1/2mv^2 and G.P.E.=mgh. For W.D., I may find F but I don't know x. For K.E., I know m but not v. For G.P.E. I don't know h. How am I to find h?
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    Solving Force and Motion Problems with the SUVAT Equations

    Homework Statement Homework Equations F=ma to find the respective accelerations of the man and the barrel. The suvat equations. The Attempt at a Solution I tried making 2 equations to solve them simultaneously but the values I'm looking to find always cancel out. I know that s...
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    MCQ about intensity of sound waves (formula manipulation)

    A is inversely proportional to x. So if A is doubled, x will be two times less. So if A at x is 8, A at 2x will be 8/2 which is 4. Thanks!
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    MCQ about intensity of sound waves (formula manipulation)

    Obviously, but we can't find k here because we don't have a numerical value for x OR I.
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    MCQ about intensity of sound waves (formula manipulation)

    Homework Statement Homework Equations The equation that is already given + (maybe) I is proportional to A2f2. The Attempt at a Solution I took the square root of 8, 8 being the Amplitude and I being proportional to the square of A. (I make the constant of proportionality 1)...
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    Binomial expansion question that I cannot fathom

    Thanks.
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    Binomial expansion question that I cannot fathom

    You did but they're not asking for what you're doing. They're asking for the coeff. of p^4q^7, not p^4q^6 which is what you're finding.
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    Binomial expansion question that I cannot fathom

    But they're asking for the coefficient of p^4q^7, not p^4q^6. BUT 4 + 7 = 11 and 11 is not the power on the original bracket. The powers on p and q must add up to 11, but they can't over here.
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    Binomial expansion question that I cannot fathom

    Homework Statement It says: Determine the coefficient of p4q7 in the expansion of (2p-q)(p+q)10. I can find the coefficient of p4q6 in the expansion of (p+q)10 but how am I to find it for (2p-q)(p+q)10? Homework Equations Binomial expansion formula. The Attempt at a Solution...
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    Why are codons like GGG and GUG specific to glycine and valine?

    Is there a reason for this or is it 'just like that'?
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    Trouble deciding on which equation to use in this obscure problem?

    Ah, I see. Now I understand. (I haven't covered the calculus part of Mechanics yet.) Thank you both very much indeed!