# What Is Relative Force?

M. McGee
M. McGee

Relative force is a term that means different things to different people. Its actual definition is a ratio of one force against another force on the same object in the same environment. This means that if one force moves the object a certain distance and the other moved it twice the distance, then the relative force is 1:2. In addition to this definition, the term is used to compare the overall strength of different forces, such as nuclear force to gravity, and by laymen as a way of describing how much effort goes into one activity over another.

The term relative force is made up of two terms that both have very specific meanings. The first word, relative, simply means a comparison of two or more things. This comparison doesn’t necessarily have any constants or baseline figures; one thing is compared directly to the other things. For example, a direct measurement would be ‘the wall is 9 feet (3 meters) long'; while the relative measurement would be ‘this wall is twice the length of that wall.’

The exact definition of a force is much trickier. A force is anything that causes a change in something’s size, shape, mass, direction, speed, and so on. In general, forces are non-physical things; when a person pushes something, the person generates the force but is not a force himself. This basically means that forces can be just about anything that creates any form of change anywhere.

Researchers use relative force to find differences in the overall impact one force has over another. When finding relative force, researchers must have three distinct things: an object to affect, an environment with no outside variables and a method of measuring change. During the experiment, one force acts on the object and the changes are measured, then the second force does the same. The results of the two forces are compared to find a ratio that outlines their relative strength in that situation.

There are two other common places to find the term relative force. When two or more forces are compared mathematically, it is possible to find a comparison between their overall effects on the environment. These comparisons are not directly useful as data because they do not happen within a closed system using the same variables. Even so, they can provide clues as to which forces have the possibility of doing specific things.

Outside of the scientific world, relative force has a less precise meaning. When performing physical work, the amount of ‘something’ put into one job is typically compared to the amount used in another. This basically translates to ‘this job is twice as hard’ or ‘that job takes half as long.’ This is a simple ratio that compares one task’s physical energy use as effort to another based on a single variable; in the previous examples, the variables are energy expenditure and time.  