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A 079 m aluminum bar is held with its length its length parallel to the east-wes

ID: 1610554 • Letter: A

Question

A 079 m aluminum bar is held with its length its length parallel to the east-west direction and dropped from a bridge. Just before the bar hits the river below, its speed is 23 m/s, and the emf induced across is 6.10 times 10^-4v. Assume the horizontal component of the earth's magnetic field at the location of the bar points directly north. (a) Determine the magnitude of the horizontal component of the earth's magnetic field. T (b) State whether the east end or the west end of the bar is positive.

Explanation / Answer


let v be the speed


induced emf across the ends of the rod = B*v*L


6.1*10^-4 = B*23*0.79

B = 3.35*10^-5 T

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east end of the rod is positive