physics cssa 04 ^_^ (2 Viewers)

[za]

for the force question (f=bilsinx), did anyone get a really small value?
wasnt sure about mA

 

[rckl]

are you sure? is 100v?
because like the electron travel at certain speed and enter the two paralle plates...

what i did was, first i find the energy, and use another equation E=V/d^2 to find the potential difference....

but i'm not sure if i got it correct

 

[kheir]

i i only have one main thing killin me is torque 0 wen flux is max becoz the angle betwwen conductor and field is 90 or is it becoz forces cnacel outbecoz on one arm its up and on the other its down

 

[za]

wtf
i dunno wat ur talking about

 

[acmilan]

are you sure? is 100v?
because like the electron travel at certain speed and enter the two paralle plates...

what i did was, first i find the energy, and use another equation E=V/d^2 to find the potential difference....

but i'm not sure if i got it correct

Equating electric and magnetic force

qE = qvB
E = vB (and v and B were given so you can find E)

Using E = V/d
V = Ed (and d was given and you found E)


And for the torque/flux thing its because for max flux the field is at 90 degrees meaning cos 90 = 0 and torque = 0

 

[rckl]

Equating electric and magnetic force

qE = qvB
E = vB (and v and B were given so you can find E)

Using E = V/d
V = Ed (and d was given and you found E)

yeah.. i did something like that
but i didn't get 100v, the number i got is very small

 

[Enigmatic Eve]

Physics was alrite for me!!!
I was stuck on questions such as:
- shortcomings of communication technologies that led to invention of transistors (I had no clue wat it was asking.. so I made up anything to fill up the lines... praying for at least a mark!!)
- the Edison/Westinghouse question (eek!!! I've never come across these names before, so I yakked on about AC and DC generators!! I know its wrong.. but hey, I attempted the question!!)

My teacher replaced the option topic with his own questions. Thanks goodness he asked a question on ether and the MM experiment!! Yippee!!!

Yay.. trials are over for me!!

 

[snoopwogg]

Physics was alrite for me!!!
I was stuck on questions such as:
- shortcomings of communication technologies that led to invention of transistors (I had no clue wat it was asking.. so I made up anything to fill up the lines... praying for at least a mark!!)
- the Edison/Westinghouse question (eek!!! I've never come across these names before, so I yakked on about AC and DC generators!! I know its wrong.. but hey, I attempted the question!!)

My teacher replaced the option topic with his own questions. Thanks goodness he asked a question on ether and the MM experiment!! Yippee!!!

Yay.. trials are over for me!!

Its nearing the end of the high school year and he's replacing the option? havent you's finished the course?? and that shortcomings question was a perfect syllabus point, which i forgot to revise, and so is the edison/westinghouse question.. wonder why/how you havent come across it :S

 

[duffman]

hey everyone! picked up a few hints on the hard questions to come in the exam. can yous PLWEASE post the main "big marks" questions (or the syllabus part they covered)? what were the questions involving PRACTICALS on? any other hard q's aprt from transistors/technlogy and edison/westinghse?? any help would be great i have the exam in a few days.

 

[xt3rm]

does anyone have any idea about the train one? that one was really gay
i said the guy on the train saw the front one first and the back one last and the guy on eht platform saw them at the same time.

How funny was that pic of einstien in the train tho??

 

[steph@nie]

does anyone have any idea about the train one? that one was really gay
i said the guy on the train saw the front one first and the back one last and the guy on eht platform saw them at the same time.

How funny was that pic of einstien in the train tho??

isn't it the simultaneity thought experiment? with the guy on the platform thinking the lights flashed at the same time, and the guy on the train thinking that the one that he was moving towards flashed before the one behind him

 

[coroneos]

hey everyone! picked up a few hints on the hard questions to come in the exam. can yous PLWEASE post the main "big marks" questions (or the syllabus part they covered)? what were the questions involving PRACTICALS on? any other hard q's aprt from transistors/technlogy and edison/westinghse?? any help would be great i have the exam in a few days.

y cheat?y cheat?y cheat?y cheat?

 

[JimMcCool]

I found einstein halarious. Took me a while to get settled again after I realised how foolish CSSA were for doing it. Their situation was compounded by numerous spelling and gramatical errors littered throughout the paper.

 

[coroneos]

yea wtf is with that relativity of simultaneity bs qstn.. i was like omg..

 

[steph@nie]

i was hoping for it! it was one of the only things i studied in space.

 

[za]

i got that question the wrong way around. i said the person in the train saw them

hit at the same time and the guy outside saw it differently.

hope i dont lose too many marks.

 

[alexialight]

i got that question the wrong way around. i said the person in the train saw them

hit at the same time and the guy outside saw it differently.

hope i dont lose too many marks.

that's what i said as well... but i suppose it depends on which way you look at it

 

[govich]

that's what i said as well... but i suppose it depends on which way you look at it

your way of looking at it is correct. the guy on the train is in the same frame of reference as the lights.

the guy outside is in a different frame of reference and sees them come on at different times.

 

[Heinz]

your way of looking at it is correct. the guy on the train is in the same frame of reference as the lights.

the guy outside is in a different frame of reference and sees them come on at different times.

The lights arent on the train this time... thats the trick. The usual case is that light globes from the front and back of the train turn on simultaneously but this time, its outside the train (two lightning strikes). So theres a role reversal.

 

[govich]

The lights arent on the train this time... thats the trick. The usual case is that light globes from the front and back of the train turn on simultaneously but this time, its outside the train (two lightning strikes). So theres a role reversal.

my bad then. my 'source' didn't remember the question properly (i didn't do cssa, was just curious about who was right).