Mechanical energy is everywhere around us. Whether it’s a giant wind turbine generating electricity or a toddler kicking a ball, there are no physical objects that are out of its clutch.
Mechanical energy includes both kinetic and potential energy. Mechanical energy can be generated by living things, objects, water, gasses, or air. It is either the energy in motion or energy accumulated by the position (angle or location). For this reason, mechanical energy is one of the best drivers of renewable energy. Most sources of renewable energy depend on mechanical energy to efficiently generate power or transform one form of energy into another. Mechanical energy is always constant in a system (idealised system) where only gravitational forces and no significant dissipative forces, such as air resistance and friction, or one in which these forces can be neglected.
Now, let’s go through nine examples of mechanical energy in daily life.
A swinging hammer has its highest kinetic energy and lowest potential energy in the vertical orientation, in which its velocity is highest and its height lowest. On the other hand, the hammer has its lowest kinetic energy and highest potential energy at the extremities of the swing, in which the speed is almost zero and its height is highest. As the hammer starts to move, energy seamlessly transfers back and forth between these two forms of energy. Disregarding air resistance and friction at the joint, the total sum of the kinetic energy and potential energy of the hammer (mechanical energy), most of the time, is constant. In reality, the mechanical energy of a system is considerably reduced at the end of the swing by the small quantity of energy transmitted out of the system by work generated by the hammer in opposition to the air resistance and frictional forces.
Earth-Moon Orbital System
The Earth-Moon system is another important example of a mechanical system. In this case, also, the mechanical energy is almost constant, as the energy is rhythmically converted between its potential and kinetic forms. When the Moon is nearest to the Earth, it moves the fastest; potential energy is transformed into kinetic energy. When the Moon is located farthest from the Earth in its elliptical path, its speed becomes the lowest (relative). The kinetic energy of the system becomes the lowest, and the potential energy becomes the highest.
Motors convert a particular form of energy into mechanical energy. Especially electric motors convert electrical energy into mechanical energy. Usually, the usable energy is extracted as rotational kinetic energy (through an axis that revolves at a particular speed). Here, the energy conversion is conducted by the rectangular coil that is placed in a magnetic field. Electric vehicles, electric fans and electric washing machines are some of the familiar devices that use electric motors.
Wind energy is a type of energy that can be extracted from the force of winds and can also be converted into mechanical energy. The energy linked to the wind pushes the turbines of the windmills. Wind energy is the total sum of the kinetic energy of all moving particles. When the wind strikes the blades of the generator, each particle’s kinetic energy is transmitted to the axis of the electric generator. Currently, we are able to generate electricity using this mechanical wind energy. In the past, it was only used explicitly in the industrial or agricultural sectors.
Automotive Engine (Vehicle)
Automotive engines are constructed for real-world transportation operating needs. These include internal combustion engines that run using diesel, petrol, natural gas, or propane. There are also other variations, such as hybrid vehicles, fuel cell engines powered by hydrogen, plug-in hybrid engines, and all-electric engines. A gasoline motorcycle engine utilises the fuel’s chemical energy combustion to gain thermal energy. The energy gained as heat energy is used to propel a piston and produce cyclical linear movement (mechanical energy). The conversion of this cyclical motion into a circular motion to move the vehicle’s wheels.
Bow and Arrow
A bow and arrow is another simple example of mechanical energy. When an arrow is positioned and drawn (pulling back the bow and arrow system), it accumulates energy in the form of potential energy (elastic). After it is released, the bow converts the elastic potential energy into kinetic energy (motion), and the arrow propels forward. Both these forms of energy combine to enable the smooth movement of the arrow.