Induced EMF and long steel beam

AI Thread Summary
A 5.97 m long steel beam dropped from a height of 6.82 m induces an electromotive force (emf) due to its motion through the Earth's magnetic field, which has a horizontal component of 12.2 µT. The time taken for the beam to fall is calculated using kinematic equations, resulting in approximately 0.834 seconds. The magnetic flux is determined using the formula B*L, but the initial calculation of 72.8 is questioned. The discussion highlights the concept of "motional emf," emphasizing the need to consider the beam's speed as it impacts the ground. The conversation concludes with a request for further assistance in calculating the induced emf correctly.
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A 5.97 m long steel beam is accidentally dropped by a construction crane from a height of 6.82 m. The horizontal component of the Earth's magnetic field over the region is 12.2 \mu T. The acceleration of gravity is 9.8 m/s^2. What is the induced emf in the beam just before impact with the Earth, assuming its long dimension remains in a horizontal plane, oriented perpendicularly to the horizontal component of the Earth's magnetic field? Answer in units of mV.

I know that E= change in flux/change in time
To get the change in time I used the equation
x(t)= x_o +v_o*t +.5 gt^2
where x_o=v_o=0
and x(t)= 6.82 m.
solving for t gave me .834 s.
Then for the flux I think it's just B*L= 72.8... but I don't think that's right...
Can someone please help me?
 
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review something called "motional emf." THere is a variation of the emf formula for a straight conductor moving through a magnetic field in terms of its speed. Then, all you need to do is find the speed of the bar as it reaches the ground.
 
I got it... Thanks!
 
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