Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

A 0.80 m aluminum bar is held with its length parallel to the east-west directio

ID: 1332040 • Letter: A

Question

A 0.80 m aluminum bar is held with its length parallel to the east-west direction and dropped from a bridge. Just before the bar hits the river below, its speed is 22 m/s, and the emf induced across its length is 6.5 x 10^-4 V. Assuming 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, and B.) state whether the east end or the west end of the bar is positive.

Explanation / Answer

part a )

e = vBL

e = induced emf

v = velocity

B = magnetic field of earth

L = length of bar

B = e/vL

B = 6.5 x 10^-4 / ( 22 * .80)

B = 3.69 x 10^-5 T

part b ) e = v x B

v point down and B has a component in north

E has an east component

East side is positive