HSC Physics Question Thread

[CyberScopes]

how about 2016 q18
and 2014 q15 ( i never know how to solve these.. )

For your other question:

Whenever I come across these questions, it just requires some algebra and assuming. Some people do it a more 'common sense' sort of way but when I use algebra it just makes much more sense in my head.

For this, use F = GMm/d²
For comparison, just assume all irrelevant variables (G, M and m) are 1, it makes the whole thing easier to understand:

F = 1/d²
Now say at the start d = 1:
F = 1/1 = 1
For the new distance, say d is doubled, so d = 2:
F = 1/2² = 1/4

But since F should actually be 12 when d = 1, times the new answer by 12:
F = 12/4 = 3N

Answer should be A

[khadeeja_]

For your other question:

Whenever I come across these questions, it just requires some algebra and assuming. Some people do it a more 'common sense' sort of way but when I use algebra it just makes much more sense in my head.

For this, use F = GMm/d²
For comparison, just assume all irrelevant variables (G, M and m) are 1, it makes the whole thing easier to understand:

F = 1/d²
Now say at the start d = 1:
F = 1/1 = 1
For the new distance, say d is doubled, so d = 2:
F = 1/2² = 1/4

But since F should actually be 12 when d = 1, times the new answer by 12:
F = 12/4 = 3N

Answer should be A

i kind of just messed around with stuff and i got 3 as well, is this way alright too?
1/d^2 is proportional to F
so when d is doubled --> 1/2d^2 = 12/2 (since d is inversely proportional, multiplying d with 2 would mean dividing 12 with 2)
and then d^2 = 3

[jamonwindeyer]

Dammit why are you so quick give us a chance 

Your method was completely different to mine, so I'm glad you chimed in as well!

[winstondarmawan]

Hey Jamon, I found a question that is troubling me.
https://scontent-syd2-1.xx.fbcdn.net/v/t34.0-12/22894992_1364158777042975_445018130_n.png?oh=f95370301f82d11379b817756f62a61e&oe=59F7EA1B
It was similar to the one that I asked you about why the copper slit ring falls at the same time as the plastic ring, however this question is suggesting that it is indeed different.

[CyberScopes]

i kind of just messed around with stuff and i got 3 as well, is this way alright too?
1/d^2 is proportional to F
so when d is doubled --> 1/2d^2 = 12/2 (since d is inversely proportional, multiplying d with 2 would mean dividing 12 with 2)
and then d^2 = 3

Hmm not sure since the answer gives d^2 = 3 not F = 3 or 1/d² = 3, but I can see where youre going, maybe you can try something like this?

F∝1/d²
For when F = 12:
12 = 1/d²
Now double d:
12 = 1/(2d)²
12 = 1/4d²
3 = 1/d²

Force becomes 3 once d is doubled

[sidzeman]

I'm a bit confused about the Einstein and Planck "is science removed from social and poltiical (SAC) factors" dotpoint
Some sources say Einstein believed science was not removed - had a direct impact on the nations goals and so should not be used to advance dangerous agenda's e.g Nazi Party

However other sources say that it was Planck who believed that science was removed - that advancements in science should be persued regardless of the possible use to commit atrocities.
Both arguments are correct, but which is the one that BOSTES expects?

[jamonwindeyer]

Hey Jamon, I found a question that is troubling me.
https://scontent-syd2-1.xx.fbcdn.net/v/t34.0-12/22894992_1364158777042975_445018130_n.png?oh=f95370301f82d11379b817756f62a61e&oe=59F7EA1B
It was similar to the one that I asked you about why the copper slit ring falls at the same time as the plastic ring, however this question is suggesting that it is indeed different.

Sure, and in my previous answers I've always said it is definitely different. It's just that the difference is tiny, and the eddy currents involved in both those situations are tiny anyway, so it is your call as to whether you define it as significant or not

Essentially it's like, yes, 1cm is different to 5cm. But in the context of kilometres, who really cares? Aha

[jamonwindeyer]

I'm a bit confused about the Einstein and Planck "is science removed from social and poltiical (SAC) factors" dotpoint
Some sources say Einstein believed science was not removed - had a direct impact on the nations goals and so should not be used to advance dangerous agenda's e.g Nazi Party

However other sources say that it was Planck who believed that science was removed - that advancements in science should be persued regardless of the possible use to commit atrocities.
Both arguments are correct, but which is the one that BOSTES expects?

You've correctly defined their arguments, it is just about what you define as 'removed.' I frame it as:

- Einstein believed they should be removed, that science shouldn't play a role or be weaponised in a political sense. He wasn't a patriot, didn't believe science should be used for war. Etc.
- Planck believed scientists had a duty to serve their country, and so believed science was not removed from politics.

Provided you explain your argument you'll be paid regardless

[CyberScopes]

Just wanted to say good luck to everyone in the exam tomorrow!
Make sure you:
- Read the question carefully
- Remember your SI units and converting
- Remember to use the data sheet if your lost
- Add in relevant verbs for better answers
- Manage your time well
- And most importantly dont stress out and be confident!

Oh and jamon can you give me a quick shout on your snapchat you know just sneak it in somewhere k thanks bye

[khadeeja_]

Hmm not sure since the answer gives d^2 = 3 not F = 3 or 1/d² = 3, but I can see where youre going, maybe you can try something like this?

F∝1/d²
For when F = 12:
12 = 1/d²
Now double d:
12 = 1/(2d)²
12 = 1/4d²
3 = 1/d²

Force becomes 3 once d is doubled

yupp thanks

[khadeeja_]

i dont understand why 2010 q4 is B

[jamonwindeyer]

i dont understand why 2010 q4 is B

We know that the kinetic energy will go down and up as it rises and falls (slows down then speeds up). The question is whether it hits zero, and the answer to that is no it doesn't, because it always moving horizontally! SO it always has some kinetic energy

[khadeeja_]

We know that the kinetic energy will go down and up as it rises and falls (slows down then speeds up). The question is whether it hits zero, and the answer to that is no it doesn't, because it always moving horizontally! SO it always has some kinetic energy

Thank youuuu!

[winstondarmawan]

Would appreciate help with this Q:
https://scontent-syd2-1.xx.fbcdn.net/v/t35.0-12/22908566_1364204840371702_510182205_o.png?oh=2e30420e7fbcb7cdb524e9f75b0c4cd3&oe=59F7D808
TIA!

[sidzeman]

What can MRI be used to diagnose, besides cancerous growths, and how?