EMF on cable moving in magnetic field

[amiemgm]

Homework Statement

Our teacher just posted this question online. We have less than an hour to figure it out. Can someone help point me in the right direction.

Your team has devised an orbiting “drop cable”
system that creates an induced EMF by moving a cable through a
magnetic field. In a test, tour team drops a 30.0 km-long cable from the
space shuttle, orbiting at a speed of 8.00 x 103 m/s. The magnitude of
the earth’s magnetic field at the shuttle’s location in about 6.50 x 10-5 T.
a) Find the motional EMF induced between the ends of the cable.
Assume, and state, what the angle should be between the cable and the
magnetic field to get the largest EMF. b) If you are to estimate the
electrical power that can be provided to a satellite, what else would you
need to know? Assume a reasonable value for any unknown (Check
with instructor.) and estimate this power.

Homework Equations

Not sure? We just start this section today.

The Attempt at a Solution

 

[BigJDubs]

a) The equation for the motional EMF induced between the ends of the cable is EMF = vBL, where v is the speed of the cable, B is the magnetic field, and L is the length of the cable. Therefore, EMF = 8.00 x 103 m/s * 6.50 x 10-5 T * 30.0 km = 1.44 V. To get the largest EMF, the angle should be 90 degrees between the cable and the magnetic field. b) To estimate the electrical power that can be provided to a satellite, you would need to know the resistance of the cable, the current in the cable, and the voltage across the cable. Assuming the resistance of the cable is 0.1 Ohms, the current is 1.44 Amps, and the voltage across the cable is 1.44 Volts, then the estimated power is 2 Watts.