Force per unit length,

$\overline{)\begin{array}{rcl}\frac{\mathbf{F}}{\mathbf{\u2206}\mathbf{L}}& \mathbf{=}& \frac{{\mathbf{\mu}}_{\mathbf{0}}{\mathbf{I}}_{\mathbf{1}}{\mathbf{I}}_{\mathbf{2}}}{\mathbf{2}\mathbf{\pi r}}\end{array}}$

I_{1} = I_{2} = 3.0 A

r = 25 cm (1 m / 100 cm) = 0.25 m

μ_{0} = 4π × 10^{-7} T•m/A

Two current-carrying wires are exactly parallel to one another and both carry 3.0 A of current. The two wires are separated by a distance of 25 cm. The current in wire 1 moves down while the current in wire 2 moves up. What is the **magnitude** of the magnetic force per unit length caused by wire 1 on wire 2? What is the **direction** of the magnetic force caused by wire 1 on wire 2?