Physics CSSA (1 Viewer)

[Nuendo]

I wrote gravatational potential energy is increasing during launch as the rocket is losing mass from fuel consumption and thus losing kinetic energy. From Law of conservation of energy (state definition here) the rocket must be gaining gravatational potenial enegy as it moves upwards

Dammit, I just said during the initial stages of a launch, a large amount of fuel is needed to provide the KE to lift the rocket. Then I just said that the KE changes into GPE as time progresses and distance increases, thus, when there's a huge amount of KE that must mean there must be a huge amount of it turning into GPE - increasing GPE.

I guess I should have mentioned the conservation of energy part, and thus, KE and GPE have an inverse relationship.

 

[M@ster P]

I wrote that GPE within a gravitational field in this case Earth's is given by Ep =mgh. From that formula we can see that as the rocket is accelerating, the rocket is gaining altitude away from the earth and the height is increasing, there fore the rocket is gaining GPE during first stage.

Not sure if thats right

 

[shaon0]

I wrote gravatational potential energy is increasing during launch as the rocket is losing mass from fuel consumption and thus losing kinetic energy. From Law of conservation of energy (state definition here) the rocket must be gaining gravatational potenial enegy as it moves upwards

Yeah, I used exactly the same concept in my answer.

 

[-Onlooker-]

Anyone remember the speaker cone?
Which direction was it moving for you guys?

 

[clonestar]

The speaker cone should move to the left.
Q18 speaker cone
You should use left hand FBI agent and B is down and I is into the page making force to the left.

I honestly feel the multiple choice was very straight forward although the way the examiners tried to twist the wording of question 5 is shockingly confusing and shame on them.... this is not an English test it's physics...

Just for your information people, you might want to debate with your teacher the following questions as they are quite poor answers and probably your teacher has marked in accordance with the guidelines and not picked up the following.


Q19 b
The fools make a contradiction here and state an altitude of 260km above Earth and then in brackets state (radius of orbit 6400km). hahahahahah
There is no way the Earth's radius is 6378km and adding the altitude of 260Km makes a total radius of 6638km which will need to be converted into metres. I couldn't believe they made this error but do argue it if required to get additional marks.

Q19 c
The examiners/writers failed to state the satellite is orbiting earth. Poor assumption as the satellite could orbit any planet or even satellite e.g. moon. Here you could argue moon orbit as question does not specify this and can be argued.


Ohhh well another CSSA Physics paper..... Mehhhhhhhhhh

 

[Nuendo]

I honestly feel the multiple choice was very straight forward although the way the examiners tried to twist the wording of question 5 is shockingly confusing and shame on them.... this is not an English test it's physics...

I also thought that relativity multiple choice question about the student on the bus holding a mirror was a little overdone. I put down a), the two students on the bus stop can conclude that the girl on the bus CAN'T see her reflection because the light from her face will never reach the mirror.

But then I discussed this question with my teacher after the exam and she went on to tell me that there are heaps of errors in the answer booklet that came with the paper. So guys, be sure to check your papers when you get them back, might be able to scab some extra marks

 

[AnandDNA]

Also the wording of the mutiple choice answers to the question 'what is the purpose of a tarnsformer' was pretty stuffed up. I initially had D 'to reduce power loss when voltage is stepped up or stepped down'. But then i realised that answer is saying that power loss occurs because of step up and step down. So i circled A which said 'to control the voltages in the circuit'. Which is kind of what a tranfomrer does anyway. But yeh i think that question too is debatable

 

[annabackwards]

The speaker cone should move to the left.
Q19 b
The fools make a contradiction here and state an altitude of 260km above Earth and then in brackets state (radius of orbit 6400km). hahahahahah
There is no way the Earth's radius is 6378km and adding the altitude of 260Km makes a total radius of 6638km which will need to be converted into metres. I couldn't believe they made this error but do argue it if required to get additional marks.

Q19 c
The examiners/writers failed to state the satellite is orbiting earth. Poor assumption as the satellite could orbit any planet or even satellite e.g. moon. Here you could argue moon orbit as question does not specify this and can be argued.


Ohhh well another CSSA Physics paper..... Mehhhhhhhhhh

Actually, that is about the Earth's radius and if you don't believe me take a look at what wiki has to say: Earth radius - Wikipedia, the free encyclopedia. I don't know how many past papers you've done, but they usually do tell you the altitude above the earth, expect you to know to add this to the earth's radius and convert is into metres...

Also the wording of the mutiple choice answers to the question 'what is the purpose of a tarnsformer' was pretty stuffed up. I initially had D 'to reduce power loss when voltage is stepped up or stepped down'. But then i realised that answer is saying that power loss occurs because of step up and step down. So i circled A which said 'to control the voltages in the circuit'. Which is kind of what a tranfomrer does anyway. But yeh i think that question too is debatable

I was also tossing between those 2 answers for that question >.>

Rest assured i'll argue with my teacher about the answers ^^

 

[kaz1]

Actually, that is about the Earth's radius and if you don't believe me take a look at what wiki has to say: Earth radius - Wikipedia, the free encyclopedia. I don't know how many past papers you've done, but they usually do tell you the altitude above the earth, expect you to know to add this to the earth's radius and convert is into metres...

But they said that it was the radius of the orbit not the earth's radius.

 

[annabackwards]

But they said that it was the radius of the orbit not the earth's radius.

Really? I remember that they said it's altitude was 260km above the Earth. If not, my mistake

 

[youngminii]

CSSA papers are always ridiculous. Having looked at their past papers, their wording is so ambiguous that it truly is more of a guessing game.

 

[clonestar]

Yes.....Q5... I forgot...

The question starts by stating a "bus made of light"... This sums up the rest of the question...mind you the answer is very clear and simple...

Also the transformer question.... looking at it again reveals dodgy turns or a blotchy/poor image. I would have thought the diagram would have the turns stated in it, to clarify to students what the turn ratios is.

 

[clonestar]

Just a few more observations on this paper.

Q1 is ambiguous two possible answers earth and the new planet so B and C are acceptable.

Q8 is actually wrong in the answer booklet. They state D in the answer booklet but the real and correct answer is A based on the slope of the curve and Lenz's Law reflecting EMF. Check this one for your reference guys and argue it for extra mark.

Q17c the answer in the book states the GPE decreases. This in fact wrong. The Radius for GPE starts from infinity and when you compare Earth's surface and then lift-off the radius compared to infinity is decreasing. This decrease in radius increases the GPE and this should be the correct answer. Their answer assumes the radius begins from the centre of the earth and this is wrong based on the context of the formula GPE=-GM1M2/r

Enjoy...

 

[kaz1]

Just a few more observations on this paper.

Q1 is ambiguous two possible answers earth and the new planet so B and C are acceptable.

Q8 is actually wrong in the answer booklet. They state D in the answer booklet but the real and correct answer is A based on the slope of the curve and Lenz's Law reflecting EMF. Check this one for your reference guys and argue it for extra mark.

Q17c the answer in the book states the GPE decreases. This in fact wrong. The Radius for GPE starts from infinity and when you compare Earth's surface and then lift-off the radius compared to infinity is decreasing. This decrease in radius increases the GPE and this should be the correct answer. Their answer assumes the radius begins from the centre of the earth and this is wrong based on the context of the formula GPE=-GM1M2/r

Enjoy...

If you're a Physics teacher can you confirm the answer for Question 9?
It was the question about the egg on the induction cooktop. The original answer was B but our teacher changed the answer to C because of this there was heated argument in our class.

 

[clonestar]

If you're a Physics teacher can you confirm the answer for Question 9?
It was the question about the egg on the induction cooktop. The original answer was B but our teacher changed the answer to C because of this there was heated argument in our class.

The answer is B.

C which states Lenz's law does not combine the statement with Faraday's law as the two laws must work in tandem for an EMF(eddy current) to be produced.

I disagree with your teacher offering C as being correct as the missing words in that choice is including Faraday's law to create the eddy currents. This is missing and as a result this is a poor answer.

Also, B states free electrons which technically refers to a metal/conductor definition(copper or aluminium base pan) and the missing production of eddy currents which is why the egg has not heated.
Enjoy...