How fast is the rod moving after it has traveled 8.00 m down the rails?

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Homework Help Overview

The problem involves an electromagnetic rail gun scenario where a conducting rod is placed across two parallel rails. The setup includes a magnetic field, a current flowing through the rod, and the goal is to determine the speed of the rod after it has traveled a specific distance down the rails.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the application of various formulas related to magnetic forces and motion, including the force on a current-carrying conductor and the relationship between force, mass, and acceleration. There is an attempt to derive a formula and clarify the use of specific variables in the context of the problem.

Discussion Status

The discussion includes attempts to clarify the correct formulas to use, with some participants expressing confusion about the derivation and application of the formulas. There is a mix of responses, with one participant claiming to have found the answer while others continue to seek clarification on the underlying concepts.

Contextual Notes

Participants are navigating through the complexities of electromagnetic theory and its application to the problem, questioning the assumptions made in the original poster's calculations and the relevance of certain formulas.

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Homework Statement


An electromagnetic rail gun can fire a projectile using a magnetic field and an electric current. Consider two parallel conducting rails, separated by 0.530 m, which run north and south. A 49.0 g conducting rod is placed across the tracks and a battery is connected between the tracks, with its positive terminal connected to the east track. A magnetic field of magnitude 0.750 T is directed perpendicular to the plane of the rails and rod. A current of 2.00 A passes through the rod.
If there is no friction between the rails and the rod, how fast is the rod moving after it has traveled 8.00 m down the rails?

Homework Equations



a=(IL(([mu0(I))/(2\pi*r)))/m
v=sqrt{2ad}

The Attempt at a Solution



(2(.530)(4pi-7(2))/(2pi(.53))/.049 = 1.63e-5
sqrt{2*1.63e-5*8}=.016

this answer is wrong. can you please tell me what i am doing wrong and help me out?Thanks.
 
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Sweet, I don't recognize that formula! Can you derive it from basic formulas for us? I would expect you to use Fm = I*L*B in this problem - the formula for the magnetic field causing a force on a current.
 
i got the answer, thanks for trying to help
 
Sorry, I'm still not with you. I see you are using F = ma but why not
F =ILB? Where does the mu and pi come from? I would begin with
F = ma
ILB = ma
 

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