4 (10 points) A popular demonstration done in class involves suddenly switching on of a current in an electromagnet or coil that launches a copper 5/ ring which was initially resting above the coil, Explain how this repulsive force arises in the ring due to the current induced in the ring. Assume that the B field points up in the direction of the ring after the switch is closed. Specifically show the resulting induced current in the ring and subsequent forces on the ring. _|