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% 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...

Particles undergo no disturbance at an antinode? I thought antinodes were points of maximum displacement?

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.

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...

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?

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...

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!

Obviously, but we can't find k here because we don't have a numerical value for x OR I.

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)...

Thanks.

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.

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.

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...

Is there a reason for this or is it 'just like that'?

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