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Re: HSC 2015 3U Marathon Next value (I think) given below and hint for denominator and numerator

re: HSC Physics Marathon Archive The marking criteria has changed for superconductivity, especially due to recent advancements in understanding (i.e., flux pinning or quantum flux trapping) I really doubt that big questions of superconductivity will arise. They USED to want you to talk...

For HSC sake, we must say that it 'brought into question' the existence of the aether Einstein himself said the following: "The next position which it was possible to take up in face of this state of things appeared to be the following. The ether does not exist at all. The electromagnetic...

re: HSC Physics Marathon Archive Without understanding where the equation comes from, you would be unable to answer the question which I posed. Most students would cite energy losses due to eddy currents etc.. But that affects the current ratio, not the voltage ratio. Transformers operate on...

re: HSC Physics Marathon Archive Therein lies the assumption! That the rate of change of flux experienced by both coils is the same, i.e., no flux leakage. Forget about internal resistance! LoL.

re: HSC Physics Marathon Archive You need to understand where the equation arises from. Energy losses will not affect this particular equation.

re: HSC Physics Marathon Archive New Question: Assess the validity of the transformer equation Vp/Vs = np/ns (3 marks)

re: HSC Physics Marathon Archive I would give this A 3 or 4, probably a 4. A few minor (but key) points missing - no description of AC induction motor (stator consists of 3 pairs of opposing electromagnets each connected to a different phase of 3 phase AC supply, rotor consists of bars...

Mate, Your fizzicks is on point! Kudos to you! What are you studying at uni?

re: HSC Physics Marathon Archive Explain how an AC induction motor operates (5 marks)

Bump, bump, bump. Still need some keen 2016ers to join my bunch of uber nerds

Induction coils are DC, but they contain an interrupter, this basically switches the current on and off --> creates change in flux --> induces current in secondary circuit. I tell my students that there are little Russian people in the induction coil switching the flow of current on and off...

This is quite a good qualitative description which I give to my students http://www.physics.usyd.edu.au/~khachan/PTF/Superconductivity.pdf The mathematics, however, is beyond high school mathematics. Unless you for some reason have an understanding of wave functions and thermodynamics, the...

Bump for keen 2016ers :)

Radius + altitude. r is how far the object is from the CENTRE of the planet

re: HSC Physics Marathon Archive Have a go at answering it for 5 marks :)

re: HSC Physics Marathon Archive Compare the EMF induced in a simple DC motor and an AC induction motor (5 marks)

Re: HSC 2015 3U Marathon I get an answer of 0.231.. Don't know if my thought processes are intact though

Re: HSC 2015 4U Marathon A car takes a banked curve of a racing track at p m/s, the lateral gradient angle \phi being designed to reduce the tendency to side-slip to zero for a lower speed q. Show that the coefficient of friction necessary to prevent side-slip for the greater speed p must...

Re: HSC 2015 4U Marathon That was fun :) I get: x1 = -25 x2 = -19 x3 = -7 x4 = 17 x5 = 65