HSC Physics Question Thread

[shreya_ajoshi]

That's correct if the masses were all M, M, M and not M, 9M, 16M. But I don't think that was what you typed at the time though...

Oh okay, but the question does say M,9M and 16, so I'm not too sure anymore haha

[Happy Physics Land]

a) t=d/s
∴t=8/0.5
∴t=16 years

b) using the formula t(v)=(t(o))/sqrt((1-(v^2/c^2)))
sub in the values such that t(o)=16 and v=0.5c
∴t(v)=18.48 years

c)d=s*t
∴d=0.5c*18.48
∴d=2.77x10^9 m

d) This is a trick question as the astronauts cannot measure the speed inside their inertial reference frame unless sourced from an external reference frame.

Good stuff there rathin my friend

[bluecookie]

Draw the field lines. Use crosses to signify lines into the page, and dots to signify lines out of the page. For anti-parallel wires, you'll find that you get only dots between the wires (or only crosses). As like charges repel, both wires will repel each other, resulting in the left wire experiencing a force to the left.

My book said nothing about like charges repelling. It just said to use the right hand grip rule for the first wire, and then the right hand palm rule for the second wire. It worked for parallel lines. However when I tried it with anti parallel lines (with the first line pointing up for reference) I got crosses between the wires, and then using the right hand palm rule on the second wire I got a force going to the right. However, seeing as the first wire generates a magnetic field pointing to the right, doesn't it mean the first wire moves to the right also? So I got they're both going right, but the book says they should repel. I don't understand how the first wire is meant to be moving to the left?

[RuiAce]

My book said nothing about like charges repelling. It just said to use the right hand grip rule for the first wire, and then the right hand palm rule for the second wire. It worked for parallel lines. However when I tried it with anti parallel lines (with the first line pointing up for reference) I got crosses between the wires, and then using the right hand palm rule on the second wire I got a force going to the right. However, seeing as the first wire generates a magnetic field pointing to the right, doesn't it mean the first wire moves to the right also? So I got they're both going right, but the book says they should repel. I don't understand how the first wire is meant to be moving to the left?

Like charges repel is the same thing as saying

Two positive charges repel
Two negative charges repel
(But a positive charge and a negative charge attract)

Just like how with magnets, two north poles repel.

[bluecookie]

Like charges repel is the same thing as saying

Two positive charges repel
Two negative charges repel
(But a positive charge and a negative charge attract)

Just like how with magnets, two north poles repel.

Thanks

[Aaron12038488]

To achieve a band 6 for any subject, do you have to get 90/100 in the HSC exam?

[FallonXay]

To achieve a band 6 for any subject, do you have to get 90/100 in the HSC exam?

After the mark is aligned, yes. (It isn't a 90 raw mark)

and extension subjects should be 45+ for an E4

[Rathin]

To achieve a band 6 for any subject, do you have to get 90/100 in the HSC exam?

Its normally around 82 Raw mark which aligns to 90. But give or take one depending on the difficulty.

[RuiAce]

To achieve a band 6 for any subject, do you have to get 90/100 in the HSC exam?

If we're talking about raw marks, no.

Alignment is a process that the BOSTES uses (you can research it if you want) to address the fact that different courses have harder exams in different years. A board of members called 'judges' are responsible for determining the alignment algorithm that gets applied that year.

Because the algorithm is different, it is never possible to say with certainty how much you need to score raw to get aligned to 90 (or whatever mark in question). As per the raw marks database, however, historically it is approximately 83. Subject to about plus/minus 4 inaccuracy.

Post-alignment, however, you must have achieved at least an average of 90. This average is between your moderated AND aligned internal mark, as well as your aligned HSC exam mark.

For further reading, find Jamon's article

[Aaron12038488]

So I'm going to start Year 11 in a couple of weeks. What equipment should I take with me. My school hasn't told us what to bring.

[FallonXay]

So I'm going to start Year 11 in a couple of weeks. What equipment should I take with me. My school hasn't told us what to bring.

The usual school equipment?
• Notebooks
• Diary (personal preference, or my school provided one)
• Laptops (if your school needs one)
• Pencil case (Pens, pencil, highlighter, whiteout, glue, scissors, sharpener, ruler, etc.)
• A calculator
• A geometry set (maybe not needed at the beginning of the year, but nice to have if you're doing mathy/sciency subjects and want to be neat )

[Aaron12038488]

This holiday I have been studying The World Communicates Topic. I'm almost finished it, so should I memorise everything before school starts. This will give me an edge and make me confident.

[jakesilove]

This holiday I have been studying The World Communicates Topic. I'm almost finished it, so should I memorise everything before school starts. This will give me an edge and make me confident.

If it's going to make you feel better about your course work, and make you more confident, then go for it! Whilst not absolutely necessary, you should be studying in whatever way makes you the most comfortable

[jamonwindeyer]

This holiday I have been studying The World Communicates Topic. I'm almost finished it, so should I memorise everything before school starts. This will give me an edge and make me confident.

You can if you like! But remember that your Year 11 content isn't assessable at the HSC Level (for World Communicates, you essentially need to know a formula in the HSC, which they give you on the reference sheet anyway), so don't stress about it too much! Year 11 is a time to develop good habits and figure out how you work best - I regret putting as much stress into Year 11 as I did just studying the topic is way more than I ever did!

[Swagadaktal]

This holiday I have been studying The World Communicates Topic. I'm almost finished it, so should I memorise everything before school starts. This will give me an edge and make me confident.

TBH I wouldn't even recommend doing this for a year 12 study, letalone a year 11 one!
It's not sustainable to be doing this so early on and it doesn't really provide you with much of an edge, because there is more than enough time during the actual year to learn the content!

I'd strongly recommend taking a more sustainable approach