Physics

PHB

How'd it go.
I though it was a lovely paper!

The_Keeper

yea it was a pretty good paper

i feel i answered everything correctly but physics always seems to find a way to screw me over... but i'm confident i'll get at least 70+

section A was very nice

Q5 was good
Q7 - sound was great

Q11 + 12 were also very nice

Q10 - options looked horrible so i avoided it

Q6 was also an easy question

so over all dam good paper

Tazzle

/me makes retard gestures

DSMe

ah ****e... i thought there was 100 ... u know milisomething is usually 100

Sev

Most perfect paper yet as far as I'm concerned, answered every question perfectly except part (c) and (d) of question 12, didnt have time to finish those. I'm kicking myself tho cos I didnt spot the final 6 mark part to the sound question tho, goddamn it. No matter how many times I look over the paper....

I'm glad I remembered Stoney too, for that electron question.

Sev

A millisecond is a thousand of a second, as is millianything. Milli means x 10^-3.

Boston

Very good, thought it was excellent, i had to laugh when 1/u +1/v question came up after yesterday. Also i believe eireboy will have some egg on his face "boyles law wont come up in section a"

One thing thought, why does the sky driver achieve terminal volocity, i could have explained it use differenciation and then said as t tend towards invinity and all that crap but it seem to be to difficult for physics. I to remembered stoner.

Btw i started all my scales from o

eirebhoy

Physics was my best paper this year. I got about 75-82%. I found Q10a a bit hard though. The experiments were super Q5 was easy. But in Question 6 It asks "Describe an Experiment to find the resultant force of two vectors", I described the sum of the ups on a metre stick equal the sum of the downs, is that what your supposed to do?

Also, what is the difference between temp and heat?

Sev

Originally posted by Boston
Very good, thought it was excellent, i had to laugh when 1/u +1/v question came up after yesterday.

Yeah, also kinda ironic that no graph was asked for it, after all that fuss about graphing it yesterday.

Darth_Jman

'twas a very nice paper indeed.
Radiation was a joke of a question!
The only things I didnt get was guy who named the electron (damn you, Stoner! Should have made your name easier to remember!), and the experiment for showing sound is a wave. I know you could have put down the speed of sound one, or any of the sonometer ones (arguing why its valid etc), but in the end I made up one with an oscilliscope and a microphone. Do experiments, per se, have to *be* on the course to get marks for these types of questions?

Apart from that, one damn fine paper. A no bother!

Sev

For that terminal velocity question, I said that the force of air resistance is dependent on the velocity of the diver, and as his velocity increases there comes a point at which the air resistance is equal to his weight, so there is no longer a resultant force and he no longer accelerates downwards but remains at a constant velocity.

I did a great picture for that question, I hope I get bonus marks for my artwork.

PHB

Yeah I did the same ste.

Air resistance is proportional to velocity, so a terminal velocity is reached once the air resistance is equal to 90g

CuLT

Substantially better than I thought it would be, still, can't really tell how I did .

Sev

For the experiment showing sound is a wave, I wasnt sure exactly what one to do, couldnt remember if there were any better demonstrations in the book. Anyway I did the demonstration to show that sound undergoes constructive and destructive interference and is hence a wave in nature. The one with the speakers placed apart emitting same frequency. Not too bothered about that question tho, I have 7 other Section B questions answered perfectly to choose from.

Neil3030

Physics was a P155!!!

Section A - Ok, Joules law, boyles law and the focal length of a converging lens??? PISS EASY!! JC STUFF!!

Section B - Q5 was a stroll in the park!! Q6: Vectors! Perfect question. Then The Doppler effect and waves in Q7!! Question 8 was dead handy, all just graphs and no theory!! And question 12!!! HA!! thermometric properties and electromagnetic induction!!!

100 points in my back pocket baby!!!

Boston

Originally posted by Sev
For that terminal velocity question, I said that the force of air resistance is dependent on the velocity of the diver, and as his velocity increases there comes a point at which the air resistance is equal to his weight, so there is no longer a resultant force and he no longer accelerates downwards but remains at a constant velocity.

I did a great picture for that question, I hope I get bonus marks for my artwork.

You two lads do applied maths? This is exactly what i thought, but then i said it can't be because A) no mention of weather or not to take into account air resistance b) What your taking about is that acceleration = v dv/ds which is applied maths and not on the physics course, so i don't know how they would except an average physics sudent to get that. I'd say you would get most marks for the diagram and few for the explaination. I did A B and C any so it didnt really matter

Sev

Oh, for the resultant of two vectors, I think they intended you to use that demonstration in the book with the 3 interconnected spring balances, the magnitude of the force on one balance, being the vector sum of the other two forces. Anyway, thats what I said.

Boston

Originally posted by Sev
For the experiment showing sound is a wave, I wasnt sure exactly what one to do, couldnt remember if there were any better demonstrations in the book. Anyway I did the demonstration to show that sound undergoes constructive and destructive interference and is hence a wave in nature. The one with the speakers placed apart emitting same frequency.

That is the one your ment to do, i did it, though you would have to meantion that they had the same wave lenght

Sev

Yeah, I'd agree. That was a comment I made coming out of the exam hall, that the question was very applied mathsy.

Same frequency => same wavelength. I think I'll get by on that one. Either way, I'd say its more about the frequency than the wavelength, unless you start mentioning that one wave is moving faster than the other, which isnt going to happen.

After all the definition of coherent source is based on the fact they have the same frequencies and are in phase or have a constant phase difference.

pseudonym

physics woz lovely, got an extra q done and had time to spare

Neil3030

I just did the one where you hold the struck tuning fork over the microphone connected to the oscilliscope.

Boston

Originally posted by Neil3030
I just did the one where you hold the struck tuning fork over the microphone connected to the oscilliscope.

And what did that prove? isn't that just to get the frequency of the tuning fork, which isn't even an experiment of our course, but is on the a levels. How do you get the frequency? its writen on the side of the tuning fork!

Darth_Jman

Thats what I did (just didnt have a tuning fork).
If you make a sound, you see its waveform on the oscilliscope screen, which is a) a sine wave and b) in the form of a transverse *wave*

Sangre

Frequency for a tuning fork is written on it.

You could strike a tuning fork and then twist it near your ear showing interference.

The only I didnt get was that Stoney guy.
A1 me thinks.

Sev

The marking scheme can be quite broad in its range of accepted answers. I wouldn't rule that out altogether.

For example last year, you were asked to describe an experiment to demonstrate the photoelectric effect. Now the typical textbook demonstration is the one with the zinc plate on the negatively charged electroscope being shined with UV light.

But they also accepted, and gave full marks for, the one involving the set up of a circuit with a photocell (the one used to prove that the current produced is proportional to light intensity) as an acceptable experiment to use. I used the latter as an answer in my mock paper, and my physics teacher barely gave me any marks for it that scabby bastard.

Darth_Jman

Either way though, I dont thing it will be counted. If anyone has read the marking schemes for any physics paper, they list answers to those types of questions. Depends on the examiner you get I suppose

Neil3030

I read somewhere that it was acceptable. I completely forgot about the interference experiment so i decided to go with the oscilliscope one.

PHB

A) no mention of weather or not to take into account air resistance

I would assume you just sasume there is air resistance, as you are not told otherwise.
There is no other way to explain terminal velocity except assumign there is air resistance, or is there :P

Non the less, I did all four parts anyway

Sev

What's funny is, that just last night I was telling SOL about Question 11, the story question, the one that says "Read the following passage and answer the following questions" and about how every time I end up finishing question 11 in an exam, I ask myself why I bothered to waste my time to read it in the first place, its always so goddamn irrelevant.

Anyway, as it happens, I flew through that question in about 5 minutes, completely forgetting to read the paragraph in the first place, only glancing up for a second to spot the figure for the half-life. What a stupid, stupid question.

eirebhoy

Oh, for the resultant of two vectors, I think they intended you to use that demonstration in the book with the 3 interconnected spring balances, the magnitude of the force on one balance, being the vector sum of the other two forces. Anyway, thats what I said.

in Question 6 It asks "Describe an Experiment to find the resultant force of two vectors", I described the sum of the upward force on a metre stick equal the sum of the downward, is that what your supposed to do?

Please put my head to rest and tell me if the Metre stick explaination would be acceptable and able for full marks!

Sev

It sounds wrong, I couldn't tell you how wrong tho.