To a scientist, work is done when a force causes something to move. The unit of measurement used for work is the joule. A joule of work is done when a force of one newton moves something one metre (3.3 feet). The force needed to lift a small apple is about one newton.
On a typical day, you probably wake up, get dressed, eat breakfast, and head off to work. After you spend all day at your job, you go home, eat dinner, walk the dog, maybe watch some TV, and then go to bed. In this sense, work can be just about anything – construction, typing on a keyboard, driving a bus, teaching a class, cooking food, treating patients, and so much more.
But in physics, work is more specific. This is the displacement of an object due to force. How much work is done depends on the distance the object is moved. This makes it easy to put work into a solvable equation: work = force * distance. While this equation is fairly straightforward, there are three important things to note. First, the object must move over some distance in order for work to be done. Second, the force and the distance of movement must be in the same direction. And finally, the force must be constant.
The units we use for work are joules (J), named for James Prescott Joule. Though he is now known for his work in science, he actually preferred brewing beer… until he realized how science could help him be a better brewer!
The joule is a combination of both of the components on the right side of our work equation: force and distance. Quite simply, a joule is a Newton-meter (N*m), and one joule of work is done when a force of 1 N is exerted over a distance of 1 m.
This amount of work is on par with lifting an apple over your head. I bet you didn’t realize that counted as work, but in the world of physics, it does! You can probably see that 1 J isn’t really practical to use for larger amounts of work, so instead we use kilojoule (kJ), which is 1000 J, or megajoule (MJ), which is 1,000,000 J.
Regardless of the amount of work done, it involves three key components: the amount of force, the distance displaced, and the cause of the displacement, which is the force itself.
Picture Credit : Google