Mechanical vibration refers to the oscillatory motion of mechanical systems, where objects or structures vibrate about their equilibrium positions. These vibrations can be caused by external forces, such as friction or impact, or by internal forces, like imbalance or misalignment. Mechanical vibrations can be classified into different types, including free vibration, forced vibration, and self-excited vibration. Understanding mechanical vibration is crucial in designing and analyzing systems, such as engines, gearboxes, and structures, to minimize vibration-induced damage, noise, and fatigue, and to ensure safe and efficient operation. By applying principles of vibration analysis, engineers can predict and mitigate potential vibration problems.