Magnetic field, current, and a slide wire

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Homework Help Overview

The problem involves a U-shaped conducting rail in a magnetic field, with a slide wire that can move vertically. The question asks for the terminal velocity of the slide wire when released from rest, given specific parameters such as length, mass, resistance, and magnetic field strength.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between electromotive force, current, and the forces acting on the slide wire. There is uncertainty about the relevance of mass in this context, with some questioning its role in the problem.

Discussion Status

The discussion reflects a mix of confusion and realization, with one participant acknowledging a misunderstanding of the problem's details. There is an ongoing exploration of how the given parameters relate to the overall question, but no consensus has been reached on the role of mass.

Contextual Notes

Participants note the lack of explicit information regarding the electromotive force and express confusion about the significance of mass in relation to the problem's setup.

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Hi, I really need help with this question.

Here's the question:

"The figure shows a U-shaped conducting rail that is oriented vertically in a horizontal magnetic field. The rail has no electric resistance and does not move. A slide wire with mass m and resistance R can slide up and down without friction while maintaining electrical contact with the rail. The slide wire is released from rest."

"Determine the value of a terminal velocity if l = 25.0 cm, m = 10.0 g, R = 0.100 ohms, and B = 0.550 T."

I know that V_emf = vlB
I = V/R = vlB/R
If I can find I, then I could determine v. The problem is they don't give V_emf, so I cannot find I. and I have no idea why would they give the mass for, when generally for this type of problem they don't. Any hints would be greatly appreciated.
 

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F = IlB
P = Fv = (v^2)(l^2)(B^2)/R

I just don't see how could the mass be relevant to this problem. If it was a particle then may be I could use the mass to do something with the circular motion but this just doesn't make sense. Please help.
 
I think I might get it now, I just didn't read the question carefully and miss the "vertical part".
 
:eek: OK, I got it, still cannot believe I could miss the keyword "vertical". Thanks and sorry for this. Please don't get mad at me. I'm going to sleep now at almost 8 A.M. :zzz:
 

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