1) A 0.79-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 16 m/s, and the emf induced across its length is 5.2 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. (a)

(b)

2) In 1996, NASA performed an experiment called the Tethered Satellite experiment. In this experiment a 2.37 x 10⁴-m length of wire was let out by the space shuttle Atlantis to generate a motional emf. The shuttle had an orbital speed of 6.55 x 10³ m/s, and the magnitude of the earth's magnetic field at the location of the wire was 5.31 x 10^-5 T. If the wire had moved perpendicular to the earth's magnetic field, what would have been the motional emf generated between the ends of the wire

4)

5)Suppose that the light bulb in Figure 22.4b is a 60.0-W bulb with a resistance of 227 . The magnetic field has a magnitude of 0.582 T, and the length of the rod is 1.18 m. The only resistance in the circuit is that due to the bulb. What is the shortest distance along the rails that the rod would have to slide for the bulb to remain lit for one-half second?