A copper rod of length 0.50 m is lying on a frictionless table. Each end of the rod is attached to a fixed wire by an unstretched spring that has a spring constant of k=50.0 N/m. A magnetic field of strength 0.25 T is oriented perpendicular to the surface of the table as shown.

  1. What must the direction of current be in the copper rod that causes the spring to stretch?
  2. If the current is 15A, by how much does each spring stretch?