HSC Physics Marathon 2013-2015 Archive (2 Viewers)

[JJ345]

re: HSC Physics Marathon Archive

Yeah, can you explain why ?

Sure-->The relative motion between the coil and the magnetic field induce an emf (Faraday's Law) which gives rise to a current that sets up a magnetic field to oppose the original change in flux (Lenz's Law)--> For this reason we can eliminate C straight away(no relative motion).
So basically in A we want a current that will interact with the B-field to produce a north pole on the LHS of the solenoid--> as the attraction force between the poles will resist the motion of the magnet(what we want to happen)--> using right hand grip rule we can see the current given is correct.

This question is basically guess and check all the options (bar C)--> So its good that they put A as the right answer...testing all of them would be annoying.

 

[Menomaths]

re: HSC Physics Marathon Archive

Oh right, so basically where my thumb points is the N side right?

 

[ocatal]

re: HSC Physics Marathon Archive

Oh right, so basically where my thumb points is the N side right?

Pretty much..

 

[Fizzy_Cyst]

re: HSC Physics Marathon Archive

Identify a metal, metal alloy and ceramic superconductor, their superconducting type, their chemical formulae and the temperature at which they become superconducting.

Present your answer in an appropriate table.

This is my dark horse for a 3-4 mark easy question that no one will answer correctly as they all skim over it!

 

[Menomaths]

re: HSC Physics Marathon Archive

Identify a metal, metal alloy and ceramic superconductor, their superconducting type, their chemical formulae and the temperature at which they become superconducting.

Present your answer in an appropriate table.

This is my dark horse for a 3-4 mark easy question that no one will answer correctly as they all skim over it!

Yttriumniobium - YNb-90K-Ceramic
Mercury - Hg-18K- Metal
Metal alloy - 4.2K - (some funky as name)

 

[someth1ng]

re: HSC Physics Marathon Archive

Identify a metal, metal alloy and ceramic superconductor, their superconducting type, their chemical formulae and the temperature at which they become superconducting.

Present your answer in an appropriate table.

This is my dark horse for a 3-4 mark easy question that no one will answer correctly as they all skim over it!

You sir, are a cunt. LOL.

Seriously, I can remember most but not all of it. There goes 1 mark for me

 

[RivalryofTroll]

re: HSC Physics Marathon Archive

Identify a metal, metal alloy and ceramic superconductor, their superconducting type, their chemical formulae and the temperature at which they become superconducting.

Present your answer in an appropriate table.

This is my dark horse for a 3-4 mark easy question that no one will answer correctly as they all skim over it!

Can they technically ask that?

I always thought they just present you with a table with those things and ask you to analyse it and answer questions on it somehow...

 

[Fizzy_Cyst]

re: HSC Physics Marathon Archive

Can they technically ask that?

I always thought they just present you with a table with those things and ask you to analyse it and answer questions on it somehow...

Syllabus dot point:
process information to identify some of the metals, metal alloys and compounds that have been identified as exhibiting the property of superconductivity and their critical temperatures

They could ask you to identify the name, type and critical temperature, but not chemical formulae (But, I would do it anyway, just to prove ub3r nerdness!), they could ask you to do tables, graphs, flowcharts, whatever

You sir, are a cunt. LOL.

Why does everyone keep saying that to me?

 

[Fizzy_Cyst]

re: HSC Physics Marathon Archive

Yttriumniobium - YNb-90K-Ceramic
Mercury - Hg-18K- Metal
Metal alloy - 4.2K - (some funky as name)

Careful! Im pretty sure Mercury itself is 4.2K

 

[Parvee]

re: HSC Physics Marathon Archive

Why does everyone keep saying that to me?

lol

 

[Menomaths]

re: HSC Physics Marathon Archive

Careful! Im pretty sure Mercury itself is 4.2K

I swear mercury was supposed to be 4.2...Typo'd. Anyways I think I've memorized them all now

 

[omgiloverice]

re: HSC Physics Marathon Archive

 

[skillstriker]

re: HSC Physics Marathon Archive

3.2 x 10^23 kg ?

 

[omgiloverice]

re: HSC Physics Marathon Archive

3.2 x 10^23 kg ?

Correct~

 

[hayabusaboston]

re: HSC Physics Marathon Archive

Correct~

Was it 3.62x10^23?

 

[omgiloverice]

re: HSC Physics Marathon Archive

Was it 3.62x10^23?

The values are quite similar. Can I see your working out?

 

[hayabusaboston]

re: HSC Physics Marathon Archive

The values are quite similar. Can I see your working out?

Havent revised calculations from module 1 for ages lol, so my understanding of things could be wrong.

delta(y)=u_yt+1/2at^2, sub in delta y as 2, u_y as 0, t as 1.1, then u get 1=1.1^2.a, and a=1/(1.1^2)

Now F=Gm1m2/r^2, so m1a=Gm1m2/r^2, cancel m1's off both sides, times by r^2 (Is r 2563000 or 2563002? lol I cant decide, but both give u same result if rounding to 2DP anyway) and divide by G for m2, the mass of the planet.

The reason why I posted my alternate answer was becaused u said "Correct ~" and iirc the ~ means approximately? lol idk. Anyway yea.

And with the induction motor Q, induction motor part of syllabus is the ONE part I just cbf studying haha, I somehow dont feel like it will be in the HSC, idk why.
(Nek minnit, 8 marker on induction motors in hsc LOL, fuuuck that would kill me...)

 

[omgiloverice]

re: HSC Physics Marathon Archive





Careful of silly mistakes. :L

 

[Fizzy_Cyst]

re: HSC Physics Marathon Archive

Mount Everest is the worlds tallest mountain, however, it is not the point on the Earths surface at which acceleration due to gravity is the lowest. Explain.

 

[JJ345]

re: HSC Physics Marathon Archive

Mount Everest is the worlds tallest mountain, however, it is not the point on the Earths surface at which acceleration due to gravity is the lowest. Explain.

Altitude is not the only factor affecting acceleration due to gravity, its value is also affected by:
Earth's Rotations-Creates a centrifugal effect at the equator slightly lowering the value of g
Thickness of Earth's Crust-Varies and contains dense mineral deposits and tectonic plate boundaries which alter the value of g
Earths Shape-The earth is not a perfect sphere but is slightly flatter at the poles-->Thus the value of g is slightly higher at the poles (closer to the centre of the earth)
All these factors contribute to the value of g, thus simply assuming the relative value of g at a particular location based upon one criteria (ie altitude) does not necessarily hold.