CSSA Physics (1 Viewer)

[Screamm]

overall it was pretty easy except for some of the questions that got swapped because we haven't finished ideas yet :\
for the coil question did anyone else get 6.7A something for the current?

 

[jamesfirst]

Re: Question on difficulty of CSSA physics

I dont know which one I chose actually.

 

[BobMac]

overall it was pretty easy except for some of the questions that got swapped because we haven't finished ideas yet :\
for the coil question did anyone else get 6.7A something for the current?

If I remember correctly I got 2A, friends got 2,3,1 and some nut got 4000.

 

[jamesfirst]

overall it was pretty easy except for some of the questions that got swapped because we haven't finished ideas yet :\
for the coil question did anyone else get 6.7A something for the current?

I got 2.2A

 

[imZerroo]

2.02 A up the page? or out of the page, i dont remember but it was 2.02 A woooo, 2 marks.

 

[tomdoml]

Answer should be 1 A, or something around that. Got 10 in the exam cos I did it with with 0.05 kilograms instead of 0.005 kilograms lol D:

 

[jamesfirst]

Answer should be 1 A, or something around that. Got 10 in the exam cos I did it with with 0.05 grams instead of 0.005 kilograms lol D:

Dude how did 0.05 g become 0.005 kg ?


Edit: I'm most definite that I'm right. I don't remember if I did 2.2 or 2.02 but it was something along those lines


and I did the current moves upwards from D to C, according to the right hand motor rule ye. I also accounted that the weight force was going into the page, because that's how I interpreted the diagram.

 

[clissold]

Re: Question on difficulty of CSSA physics

I got 2F, but I wouldn't be surprised if I was wrong that was one of the multiple choices that put me of. What did you get?

I got F..

i got 3F on that one

the wire on the left applies a force of F to the left ( i think it was given)
and the wire on the right pushes it to the left at 2F

so 2+1 is 3

but i'm not completely sure either

I got F..

What youre saying about 2 and 1 is correct although they acted in opposite directions..

So 2 - 1 = 1

Thats if my wokring out was correct though

I think I got F ?

Im not sure.

saaame, hopefully we are right

 

[Qwertyuioplm]

Dude how did 0.05 g become 0.005 kg ?


Edit: I'm most definite that I'm right. I don't remember if I did 2.2 or 2.02 but it was something along those lines


and I did the current moves upwards from D to C, according to the right hand motor rule ye. I also accounted that the weight force was going into the page, because that's how I interpreted the diagram.

I remember a value on my calculator that was like 2.026... A. It was quite an easy question IRC.

 

[Patato]

i got ~1 amp (1.008 or something..), since there were two sides of the coil experiencing equal force which contributed to balance the weight force. so the sum of the force of both wires needed to equal weight force on point P. i think that's what you needed to do anyway..not 100% sure

 

[clissold]

omg I made that mistake too..

I said 5 grams = 0.05 kgs

GGGRRRRRRR..

ended up with an answer of ~20A so hopefully Ill still get 2 or 3 marks

 

[Screamm]

can somebody explain how they got to their answer of 2.02? i swear all my working was right >.>

 

[imZerroo]

Re: Question on difficulty of CSSA physics

i said 2F because iirc some calculation i ended up with 0.1F and 0.2F, did anyone else get those?

 

[Qwertyuioplm]

Re: Question on difficulty of CSSA physics

I'm pretty sure the 8 marker had little to do with the AC vs. DC argument of Westinghouse and Edison; the stimulus provided did mention it, however the question did not asking anything about it. Hopefully you guys weren't tricked and actually wrote a detailed analysis on how and why AC creates eddy currents (alternating current, changes in flux, induces circular current due to Lenz's Law), the effects of an eddy current (heat), the uses eddy currents have (electronic breaking, induction cooktops), the problems it faces (in reducing efficiency of transformers) and possible methods of resolving these problems (lamination). My friends have said they wrote a good essay about Westinghouse vs. Edison, and I pretty much facepalmed. Hopefully you guys didn't make the same mistake.

 

[tomdoml]

I'm pretty sure its 1.008 or something like the guy said. You can do it by equating torque on the coil produced by the 5g weight and equating it to the torque of the coil give by t=BIAcosx. If you did it the force way like some of you did you have to divide the answer by 2 since both sides of the coil contribute to the force acting against the weight.

 

[Chazure]

I'm pretty sure its 1.008 or something like the guy said. You can do it by equating torque on the coil produced by the 5g weight and equating it to the torque of the coil give by t=BIAcosx. If you did it the force way like some of you did you have to divide the answer by 2 since both sides of the coil contribute to the force acting against the weight.

lol no.

 

[tomdoml]

lol no.

confirmed for scrub

 

[josh_blick]

I got the number 2 i'm not sure if it was .2 or 2 but it was defo a 2!

 

[umz93]

Ohh crap i used Bilsin
DAMN
I worked out direction of current and force required
How many marks would i get?

 

[jamesfirst]

can somebody explain how they got to their answer of 2.02? i swear all my working was right >.>

Funny thing is, I didn't use the torque formula. BECAUSE I read the LENGTH being the given amount. It was not told that it was a square shaped coil


Okay here's what was given. The Magnitude of Flux in mT, length of the coil and the mass of the particle on the rotor


I used F = mg to get the force of the mass acting on the rotor


Then I used F = BIl to find the magnitude of the current. Which was 2.2 A or 2.02 A idk.


Then I used the right hand rule to determine the opposing force that must be acted on to counterbalance the weight force, hence the direction of the current was going towards the top.