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Thank you Is thermal equilibrium the same thing as constant temperature? On google it says: "Two physical systems are in thermal equilibrium if no heat flows between them when they are connected by a path permeable to heat." But isnt there heat flowing between a black body and its...

I understand that it doesn't transmit nor reflect any EMR, but absorbs it perfectly. 1) Why does a black body radiate? Why is it a 'perfect emitter'? 2) Does a blackbody only radiate when it becomes hotter than its surroundings? 3) If no EMR falls on a blackbody, does it still emit...

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Another mechanics question (sry trying to self-learn) I let x = 0 be the wharf and t = 0 be at 1:10 am which would mean the endpoints of the tidal motion are x = -1 and x = 0.4. Since we are told it is SHM, we can deduce x = a\cos{(nt+\alpha)} + b Can we immediately deduce b = -0.3 since it is...

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Why do we only consider half of the entire arc? Is it because the net force would then be 0? Also what is the physical significance of integrating from \theta _0$ to $\theta

Do you use Newton's Second Law tangentially to show \ddot{\theta} = \frac{g}{L}\sin \theta$ With \sum F = -mg\sin \theta$ and $a = L\frac{d^2\theta}{dt^2} Wouldn't it then be \ddot{\theta} = -\frac{g}{L}\sin \theta$ and how come a = L\frac{d^2\theta}{dt^2} instead of a =...

Thanks in advance

Using a copper cylinder instead of a horseshoe, If there is no vertical slit, If there is a vertical slit, eddy currents are still induced in the thickness of the conductor but are weaker. For the HSC though I think you have to assume that they aren't induced, and that they can ony be...

Re: HSC 2018 MX2 Marathon Sketch the locus of z and note that the modulus and argument of z use the join of the origin to a point on the circle.

100 2U

http://educationstandards.nsw.edu.au/wps/portal/nesa/11-12/hsc/results-certificates/merit-lists/first-in-course

Anyone know when the Top Achievers list is released?

The list hasn't been published on NESA yet - this is from a news article

Aboriginal Studies Killara High School ParsonsElizabeth Jessie Agriculture James Ruse Agricultural High School (Carlingford) Zhang Katelyn Ancient History Lumen Christi Catholic College (Pambula Beach) Elia Seraina Biology Fort Street High School (Petersham) Charls...

Apparently they also call on Monday, not 100% sure though.

cos(-120) = cos(120) = -cos(60) = -1/2

Re: HSC 2018 MX2 Marathon $\noindent Let $z=x+yi$, then $\Re(z)=2\Im(z) \implies x=2y$. Now $z = 2y + yi \implies z^2 - 4i = 3y^2+(4y^2-4)i$. Being real, $4y^2-4=0\implies y=\pm 1 \implies x = \pm 2$. Thus, $z=\pm (2+i)

$\noindent Take the conjugate of both sides and use $\overline{z_1+z_2+\ldots +z_n}=\overline{z_1} + \overline{z_2} + \ldots + \overline{z_n}$ and $\overline{z_1 \times z_2 \times \ldots \times z_n} = \overline{z_1} \times \overline{z_2} \times \ldots \times \overline{z_n}$ and the fact that the...

Re: HSC 2018 MX2 Marathon $\noindent Cube both sides and equate real and imaginary parts, \\ \begin{align*}\quad x &= X^3 - 3XY^2 \implies \frac{x}{X} = X^2 - 3Y^2 \ (\star) \\ y &= 3X^2Y-Y^3 \implies \frac{y}{Y} = 3X^2 -Y^2 \ (\star \star) \\ (\star) + (\star \star) &: 4\left(X^2-Y^2\right) =...