Induced emf in triangle with changing area

AI Thread Summary
Two conducting rails form a right angle, with a bar moving at 7.00 m/s in a magnetic field of 0.350 T. To calculate the magnetic flux through the triangle formed by the rails and bar at t = 2.50 s, the area must be determined using the height and base derived from the bar's movement. The emf around the triangle can then be calculated based on the change in magnetic flux. The relationship for emf can be expressed as E = at^n, where the value of n needs to be established. Understanding the rate of change of the triangle's dimensions is crucial for solving these calculations.
Hyacinth42
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Two straight conducting rails form a right angle where their ends are joined. A conducting bar in contact with the rails starts at the vertex at time t = 0 and moves with a constant velocity of 7.00 m/s along them, as shown in Fig 31-44. A magnetic field with B = 0.350 T is directed out of the page.

31_56.gif


(a) Calculate the flux through the triangle formed by the rails and bar at t = 2.50 s

(b) Calculate the magnitude of the emf around the triangle at that time.

(c) If we write the emf as E = at^{}n, where a and n are constants, what is the value of n?

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Alright, I can figure this out, only I don't know how to find the rate of change of the length of the two non-moving bars. With that, I could find the area at t = 2.50 s, and the change of the magnetic flux, and I could muddle through the last one ;)
 
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Add a vertical line in the center of the diagram, from the point where the rails join to the moving bar. You do know the rate of change of this length. Can you express other sides in terms of this length?
 
Oh, I see. The height would be vt, and the base would be 2 times the height... Thank you
 
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