Falling Square Loop A vertically oriented, square loop of copper wire falls from a region where the field B is horizontal, uniform, and perpendicular to 1he plane of 1he loop, into a region where 1he field is zero. The loop is released from rest and initially is entirely within the magnetic-field region. Let the side leng1h of the loop be s and let the diameter of the wire be d. The resistivity of copper is PR and the density of copper is Pm' If the loop reaches its terminal speed while its upper segment is still in the magnetic field region, find an expression for the terminal speed.