taht 2 tube question? (1 Viewer)

[ying123123]

1 ) y did 1 tube jump? (repulsion? top one jumped) botom one had a rack to held it)
2) caculation part?
did any put it as f=mg F/l=KII/d using this fomrular?
thats all i remember form the tube
and i was somelike like 221 amps or something

 

[richz]

right,
it jumped becuz both conductors will produce a magnetic field around the other. Due to the right hand push rule, these will repel because the currents in each travel in opp directon. The bottom one couldnt move because the supports prevented it from moving down. The top one jumped up because nothing was in its way.

 

[Captain Gh3y]

right,
it jumped becuz both conductor will produce a magnetic field around the other. Due to the right hand push rule, these will repel because the currents in each travel in opp directon. The bottom one couldnt move because the supports preventing it from moving down. The top one jumped up because nothing was in its way.

das ist correct...

But how on earth were you meant to calculate the minimum current? I couldn't think how... So I said F due to repulsion had to be such that it was greater than force due to gravity, and got over 2000 amps. I'm sure that's wrong, but I coudln't think what else to do, there wasn't enough information there...

 

[richz]

do u mean correct or incorrect.

weight force, its kinda stupid, i thut that was the only force it cud exp. so weight of rod * 9.8

 

[Captain Gh3y]

I meant that you were right for the first part.

do u mean correct or incorrect.

weight force, its kinda stupid, i thut that was the only force it cud exp. so weight of rod * 9.8

Yeah, that's what I did, (weight of rod * 9.8) = k*I²/d

(I² rather than I1 and I2 because the currents were equal, since they came from the same source)

Then I solved for I, and got like 2000 amps, it seemed wrong to have a current that high. I² was like 49000 or something because the value of k is so low.

 

[exa_boi87]

Awesome .. i did the exact same thing .. and yeh it was a high value from memory

 

[B.J]

yeah that 2000 amps thing was right because the forse of repulsion isnt that strong and at 20cm imagine energy needed to jump the wire

but what the hell were you then suppose to say for its effect on transmission?

i said couldnt put wires too close together or some shit i had no idea

 

[richz]

yes thats correct, root of 49000 is 221 not 2000??

 

[ying123123]

yeah its was like 480000 (cant remember then u sqaure it)

 

[Captain Gh3y]

yes thats correct root of 49000 is 221 not 2000??

I checked with my calculator, the number I got was
I² = 4900000
I = 2213.59. Which seems too ridiculously large of a current to be correct... I may have just been off by a factor of 100 due to calculator mistakes.

 

[B.J]

yes thats correct root of 49000 is 221 not 2000??

yeh possibly 220 actually all i remember is it started with a 2 and was big
but what the hell was answer for last part?

 

[ying123123]

yeah that 2000 amps thing was right because the forse of repulsion isnt that strong and at 20cm imagine energy needed to jump the wire

but what the hell were you then suppose to say for its effect on transmission?

i said couldnt put wires too close together or some shit i had no idea

ahahahsame here i said shit too
like the repulsion can casue energy loss or some shit and damge the wires bla bla....
4 lines lol just for a mark

 

[richz]

I checked with my calculator, the number I got was
I² = 4900000
I = 2213.59. Which seems too ridiculously large of a current to be correct... I may have just been off by a factor of 100 due to calculator mistakes.

lol, u r kinda stressing me out, im not sure now, if either of us are rong its just -1 mark, cuz we did everything else rite

 

[richz]

yeh possibly 220 actually all i remember is it started with a 2 and was big
but what the hell was answer for last part?

do u remeber the actual q, i forgot.

 

[thunderdax]

I'm pretty sure I got 221 Amps for this one and was pretty sure about it but maybe wrong.
And for the last part, I said if two transmission lines were parallel one could jump off its support if there was a surge of current so they need to be held down.
Edit: Now that i remember it my answer was 200A because everything was to 1 significant figure.

 

[ying123123]

i reember l=1
d=0.1
k =given
mass was given but cant remmber something small
g=gravity
and just find II and then square it (iam not sure about the squaring)
they had to overcome gravity inorder to jump (thats wat i think)
so f=mg
and F=KIIL/d=mg
it came out like 220amps not too sure cant really remember

 

[AntiHyper]

yer i got:
I² = 49000
I = 221.36 amps

 

[B.J]

do u remeber the actual q, i forgot.

Something like why do they have to consider this in transmission lines?
Shouldnt put wires too close together or could cause damage or something is what i wrote
how the hell should i know im not an electrician, i know physics, is what i should of wrote

 

[rama_v]

Yep I got 221 amps, I did the calculation twice because I thouight hang on, this is extremely high considering its from a battery lol
But it seems thats the correct answer.

 

[Dumsum]

Yep I got 221 amps, I did the calculation twice because I thouight hang on, this is extremely high considering its from a battery lol
But it seems thats the correct answer.

Just goes to show a battery would never actually cause the tube to jump