posted by Mareena .
A copper rod of length 0.83 m is lying on a frictionless table (see the drawing). Each end of the rod is attached to a fixed wire by an unstretched spring whose spring constant is k = 79 N/m. A magnetic field with a strength of 0.13 T is oriented perpendicular to the surface of the table. If the current is 18 A, by how much does each spring stretch?