February 1, 2023

What Is Work?

Work is the scalar product of a force acting on an object and the displacement caused by the force. In the simplest case, this product is equal to the distance travelled by an object in a particular direction. In the case of a constant force, this is always a positive number.

In everyday circumstances, we often think of work as a physical activity. It can involve pushing a heavy load on level ground or lifting a book off the floor and over our head. We also often associate it with hard work, such as a marathon or writing an exam.

But in the scientific sense, some of these activities do not do any work at all.

For example, a person reading a textbook is not doing any work by holding the text up to the light and staring at it. Even if the person is moving her hand, this motion does not move the text. This is because the action of her hand does not transfer or change energy in form, as work is done when a force acts on an object causing it to move.

This is different from what happens when you lift a weight. The weight is changing its distance from the ground and this changes its energy, which is transferred to you as you move it.

We also have the example of a chain pulling on Fido. As mentioned in a previous unit, when the chain is at an angle to the horizontal, only a part of the force on Fido contributes to a horizontal displacement. The rest of the chain causes Fido to go forward without displacing her.

Another example is when someone holds a rock over their head while walking eastward across a field. If the rock moves eastward, no work is done because the rock does not have a force that is in the same direction as the distance it is moving.

If, on the other hand, a man is lifting a box from the ground to over his head, work is done because the weight of the box is changing its distance from the ground and this change in distance results in a transfer of energy from the person to the box.

Using a similar example, if a person is holding an eraser tied to a string and then pulling it up, this is not work because the person’s action only involves applying a tension force to the string as it makes to move in a circle at a constant speed. This is because the action of the string does not transfer or change energy in form, and it is not moving an object.

The goal of redefining work is to shift all workers’ time, effort, and attention from executing routine, tightly defined tasks to identifying and addressing unseen, unnoticed opportunities for growth, value creation, innovation, and development. This requires a cultural shift in how companies manage the work environment, engage employees, cultivate their creative, problem-solving, and solution development capabilities, and implement human capital practices.