Hint for part 1 of the question
The metal bar is moving across the magnetic field. This is a classic example of motional emf. (It is important to recognize that the bar is metal because most metals are conductors. If the "bar" was an insulator, like plastic, the charges would not be able to move the potential difference would be zero.)
The potential difference is measured from the voltage, V. The voltage is directly proportional to the bar's velocity, the length in the field and the magnetic field strength itself.
The copper bars limit the length of the bar in the magnetic field. Even though the steel metal bar is longer than the two copper wires, the problem states that the potential difference is measured on the copper wires. Therefore, the "length" of the metal bar to consider is the distance between the copper bars.
Hint for part 2 of the question
As the bar slides along the copper wires, there be a resistance to their motion. (This is from Lenz's Law.) The amount of resistance can be determined from the magnetic force, BILsin(θ). But the motional emf calculates the voltage. Recall, that the voltage is proportional to the current by the resistance, V=IR. Using this equation you can determine the current and then the force.
