Problem 3 – Hint 4

Since a scrap particle in a magnetic field B acquires a magnetic dipole moment m =MV, there will be a dipole-dipole attraction force between the permanent magnet (which is also a dipole), and the scrap particle. The dipole-dipole interaction force can be found by taking the derivative of the potential energy U =-\vec B\cdot \vec m.

Please submit the solution to this problem via e-mail to