A MECHANICAL ANALOG OF FIRST-ORDER AND SECOND-ORDER PHASE-TRANSITIONS

A mechanical modal that exhibits first- and second-order phase transit ions is analyzed. The possible configurations are found first by using Newtonian mechanics and second by determining the minimum of the effe ctive potential energy taken from the Lagrangian. A comparison is made between the effective potential energy method and the Landau theory o f phase transitions. Phase diagrams are obtained for the mechanical sy stem and are compared with those of a ferromagnet. (C) 1997 American A ssociation of Physics Teachers.