Power: Meaning, Definition, Types

It is the rate at which work is accomplished. It is the rate at which energy is transferred from one place to another, or the rate at which one type of energy is transformed into another. It is possible to complete a given amount of work by the means of a low-powered motor over a long period of time, or by using a high-powered motor over a short period of time. The units of power refer to the work done per unit of time, such as foot-pounds per minute, joules per second (or watts), and ergs per second. Hence, we spent one Watt of power while performing one Joule of work in one second. A horsepower measurement is sometimes used to describe the power delivered by a machine. An engine’s horsepower is approximately 750 watts. The unit was devised by James Watt as an estimate of the amount of work that a horse could perform for a few hours. He deliberately set it at a high number, on purpose. An object’s power can also be calculated as the product of the force used to move the object and the speed at which the object is travelling in the direction that the force is applied. Based on the magnitude of force F and the speed v, power equals Fν foot-pounds per minute. Power is a scalar quantity. 

P(Power) = w(Watt)/ t (Time).

Types Of Power

Average Power 

The ratio between the total amount of work or energy consumed and the total time is called “average power,” which occurs when a machine or person performs different quantities of work or uses energy at different intervals of time.  In most cases, average power is referred to as “power” as long as the context makes it clear. As the time interval approaches zero, the instantaneous power limits the average power.

Formula: Total Energy Consumed/ Total Time Taken.

Mechanical Power

The rate at which work can be done is known as “mechanical power.” It is an output of power rather than an input of power. Usually, mechanical power is measured in horsepower, but it can also be measured in watts. Mechanical power is the ability to deliver mechanical energy to a machine. It is important to remember that power is a transfer of energy. The maximum amount of mechanical power is given by Carnot efficiency if the mechanical power is derived from a heat engine, like a power station. Similarly, the mechanical power of wind turbines is limited, though in a different way, by the Betz limit. The idealised machine is lossless. This means the machine does not lose any energy during its operation. As a result, mechanical power can be analysed easily as a mechanical advantage since it is conserved throughout the duration of the output.

Electrical Power

Electrical power refers to the rate of energy transfer that occurs per unit time in an electric circuit. It is the rate at which work is performed. Usually, electricity is supplied to homes, households, and offices via the mains’ electrical lines. Transmission wires allow electricity to travel over long distances. There are a number of ways electric power is used, including motion, light, and heat. In most instances, electrical power is generated by electric generators, but they can be provided to the source where it is required by electric batteries. Voltage is the common term used to describe the phenomenon of transferring electric charge between two forms of energy. Voltage is transferred from one form of energy to another when an electric circuit is built up. Furthermore, based on electric power, there are two basic types of electric circuits. There are active devices and passive devices. 

Conclusion 

Power is connected to the amount of work done and the amount of time. Considering that work is done by forces and that forces are capable of moving objects, it would make sense that learning about power could allow us to learn about the motion of a body over time. According to calculus, power is the derivative of work with respect to time. Power increases when work is performed more quickly. When work is performed more slowly, power decreases. Considering that force equals displacement times displacement over time (F*d), and velocity equals displacement over time (d/t), power equals force times velocity. A system with high force and speed will produce more power.