Solving for the unknown variable in Motional EMF problem | Physics Homework

[flyingpig]

Homework Statement

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The Attempt at a Solution

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$$\varepsilon = IR$$

$$\varepsilon = -\frac{d \Phi}{dt}$$

$$\Phi = BA$$

$$-\frac{d \Phi}{dt} = -Bl\frac{dx}{dt} = -Blv$$

So

$$\frac{-Blv}{R} = I$$

$$\frac{-IR}{Bl} = v$$

Now I plug in and solve, is that right or did I underestimated this question completely?

 

[flyingpig]

Actually I just realize I assumed the current is running counter clockwise..

 

[flyingpig]

Actually never mind, by Lenz' Law the direction is counter clockwise for the current

 

[flyingpig]

Oh wait it says speed, so

$$\left | \frac{-lR}{Bl} \right | = |\vec{v}|$$

 

[flyingpig]

Please...I need mroe confidence.

 

[flyingpig]

I'll just trust myself...*crickets*

 

[SammyS]

Looks OK.

Your answer?

 

[flyingpig]

1m/s...