1. A wire with a mass of 1.0 g/cm is placed on a horizontal surface with a coefficient of friction 0.20. The wire carries a current of 1.5 A toward the east, and moves horizontally to the north. What are the magnitude and the direction of the smallest magnetic field that enables the wire to move in this fashion?

2. The two parallel wires are perpendicular to the page and carry currents of 3.0 A and 5.0 A into the page.

Calculate the magnitude and direction of the magnetic field:

At a point midway between the wires.

At a point 20 cm above the wire carrying the 5.0 A current.