Work, Energy and Power

Introduction

In our day-to-day life, we use the terms work, energy, and power to mean many different things, and we often use them interchangeably. In physics, however, each of these terms has precise definitions related to force and displacement. Energy is specifically used to refer to the ability to do work. Work is specifically used to refer to displacement that occurs in the direction of force applied. Power is specifically used to refer to the rate at which work is done. Each of these terms exists concerning the other. In this article, we will be studying:

1. Energy
2. Work.
3. Power

Energy

In physics, energy is the ability to do work; it is defined as “the ability to work which is the ability to exert a force causing a displacement of an object.” In simple terms, this means that energy is the force that makes things move. Energy is divided into two types: potential energy and kinetic energy. Potential energy refers to the energy exerted before an action occurs, whereas kinetic energy refers to the energy exerted during the occurrence of an action. An excellent example to understand this would be, imagine there is a rock, the rock has the potential to be moved, that is its potential energy, however the force that is exerted once the rock moves would be kinetic energy; the potential energy is converted into kinetic energy on the movement of the rock. There is a specific amount of energy in the world; energy can never be created or destroyed; it just changes its form; this is known as the law of energy conservation.

Work

In Physics, work means mechanical work. Work is said to be done when a body is displaced to some distance in the direction at which the force was applied on the application of force. In simple terms, what this means is, work is said to have occurred when there is some movement in the body that you applied force to. An excellent example to understand this would be, imagine a rock that you are pushing until the rock moves. Even though you have used force, no work will have occurred. However, once the rock moves, work will be said to have occurred. The formula for work is W= Fs (Where w stands for work, F for force, and s for displacement). The standard unit of work is the joule. There are three types of work: Positive work, Negative work, and Zero work. When there is a displacement in the same direction in which force is applied, it’s known as positive work. When there is a displacement in the opposite direction, the force is applied, known as hostile work. An example of this would be when you pick something up from the floor; as you pick it up, gravity is trying to pull it down; hence, gravity’s work at that moment becomes negative. When there is no movement even after applying force or the force is perpendicular to the motion, (imagine you are holding up an apple as you walk ahead, in that situation to work done is zero as the force applied by you to hold up the apple is perpendicular to the displacement, i.e., the direction you’re walking in) it is known as zero work. 

Power

Definition of power in physics, power measures the rate at which work is done, or energy is transferred. An excellent example to understand it is that imagines a rock is being pushed and is moving in a specific direction; the rate at which the rock is being displaced in the direction of the force applied on it would be its power. The standard unit used to measure power is the watt (W). The formula for power is P= E/t (Where P stands for Power, E stands for energy in joule, and T stands for time in seconds). Power is also measured in horsepower (hp). Based on an interval of time, power is divided into two types; firstly, the amount of power used at a specific interval of time is known as the average power (Pavg= W/t); secondly, the amount of time used at a specific moment is known as instantaneous power (Pinst=dW/dt).

Conclusion

The words power, work, and energy carry precise meanings in physics. Power stands for power is P= E/t (Where P stands for Power, E stands for energy in joule and T stands for time in seconds), work stands for W= Fs (Where w stands for work, F for force, and s for displacement), and energy stands for the ability to do work.