A homologous rod of mass M=20kg of length L=3m and of negligible cross-section rests initially on the horizontal ground chosen as a reference level for the gravitational potential energy. The rod is rotated about one end until it takes a vertical position . Calculate the variation of the mechanical energy of the system (rod, earth).

1 answer

the center of gravity moves up 1.5 meters
m g h
= 20 * 9.81 * 1.5