Mechanical engineering is the study of physical machines that may involve force and movement. It is an engineering branch that combines engineering physics and mathematical principle with material science, to design, analyses, manufacture and maintain mechanical system. It is one of the oldest and broadest of engineering branches. Mechanical engineering requires an understanding of core areas including mechanic, dynamic,thermodynamic,materials sciences, design,structural analysis,and electricity. In addition to these core principles,mechanical engineers use tools such as computer-aided design (CAD) , computer-aided manufacturing(CAM),and product life cycle management to design and analyses manufacturing plants,industrial equipment and machinery,heating and cooling systems,transport system,aircraft,watercraft,robotics,medical devices,weapons and others.