Symptoms and effects. The illustration shows severe gall infection at the upper crown area on the roots of a peach seedling. Galls form on the crown of the plant (the point at the soil line where the main roots join the stem) and on the roots. They can also form on the main stem above soil level, or on the branches. Galls first appear as small, pale, roughened lumps of tissue. They enlarge, darken, and become convoluted.
Conservation of energy. Conservation of energy, principle of physics according to which the energy of interacting bodies or particles in a closed system remains constant. The first kind of energy to be recognized was kinetic energy, or energy of motion.
In the physical sciences, mechanical energy is the sum of potential energy and kinetic energy. It is the energy associated with the motion and position of an object.The principle of conservation of mechanical energy states that in an isolated system that is only subject to conservative forces the mechanical energy is constant.ccording to the principle of conservation of mechanical energy, the mechanical energy of an isolated system remains constant in time, as long as the system is free of friction and other non-conservative forces.