Since the sum of the forces and moments acting on a dynamically loaded system may not be
zero, there may be unbalanced loads acting on the system. According to Newton's laws of
motion, an unbalanced force on a system results in motion, due to the acceleration expressed by F = MA. This information is useful in identifying problems due to dynamic loads — a simple rule of thumb states that if the piping system is moving, it is being subjected to a dynamic load.