What is D'Alembert's Principle? For a system of mass of particles, the sum of the difference of the force acting on the system and the time derivatives of the momenta is zero when projected onto any virtual displacement.

Applications of D'Alembert's Principle\n\n D'Alembert's principle is based on the virtual work principle as well as inertial forces. The following are examples of D'Alembert's principle in action: Free fall of a mass under gravity. Theorem of Parallel axis.

There are five components of physical fitness: (1) body composition, (2) flexibility, (3) muscular strength, (4) muscular endurance, and (5) cardiorespiratory endurance. A well-balanced exercise program should include activities that address all of the health-related components of fitness.

There are 3 main ways of describing the intensity of an activity  vigorous, moderate, and gentle.