A 0.77-m aluminum bar is held with itslength parallel to the east-west direction and dropped from abridge. Just before the bar hits the river below, its speed is23 m/s, and the emf induced across its length is 6.30 10-4 V. 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 horizontalcomponent of the earth's magnetic field.
b) State whether the east end or the west end of the bar ispositive. East end of the bar is positive.West end of the bar is positive.