This field of engineering is the "broadest based discipline in engineering." "Mechanical engineering deals with power, its generation, and its applicaiotion."
Mechanical engineering deals with and is focused on specific areas such as "applied mechanics, control, design, engines and power plants, energy, fluids, lubricaiton, heating, ventilation, and more.
Mechanical engineers "develop better drive systesm for converting the chemical energy of fuels into the kinetic energy of motion. More generally, mechanical engineers design and analyze sytems for the manipulation of mechanical energy. It is one of the most pervasive engineering disciplines, with multiple applicaiontions from transport systems such as aircraft, spacecraft, trains, cars, and so on."