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## Homework Statement

I am trying to solve a problem that I have invented.

It consists of a metal stick of mass

*m*, which falls by the action of gravity (

*g=constant*) within a perpendicular constant magnetic field

*B*. The direction of magnetic fiel is showed in the image.

The stick makes electrical contact with a rigid metal structure. (view image).

This generates an intensity I(t) . And this intensity generates a force on the bar that according to Lenz's law is upwards (this is the big problem)

Initial positions and velocity are showed in the image. For easiest calculations they are Vo=0 and Yo=0.

## Homework Equations

$$|\varepsilon|=\left| \frac {d\Phi} {dt} \right|$$$$\Phi=B·l·y(t)$$$$y(t)=1/2·a(t)·t²$$

## The Attempt at a Solution

I use the Second Newton's Law: $$m·a=m·g-I(t)·l·B$$

for calculate the acceleration.

But I don't know if I need to know the value of the circuit resistance, of if I can solve it with the square loop induction coefficient L (Henrios). I need to calculate I(t) and I don't know how I can do it.