Force Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.Anti-spam check. Do not fill this in! === Potential energy === {{main|Potential energy}} Instead of a force, often the mathematically related concept of a [[potential energy]] field is used. For instance, the gravitational force acting upon an object can be seen as the action of the [[gravitational field]] that is present at the object's location. Restating mathematically the definition of energy (via the definition of [[Mechanical work|work]]), a potential [[scalar field]] <math>U(\vec{r})</math> is defined as that field whose [[gradient]] is equal and opposite to the force produced at every point: <math display="block">\vec{F}=-\vec{\nabla} U.</math> Forces can be classified as [[Conservative force|conservative]] or nonconservative. Conservative forces are equivalent to the gradient of a [[potential]] while nonconservative forces are not.<ref name=FeynmanVol1 />{{rp|at=ch.12}}<ref name=Kleppner /> Summary: Please note that all contributions to Christianpedia may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here. You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see Christianpedia:Copyrights for details). Do not submit copyrighted work without permission! Cancel Editing help (opens in new window) Discuss this page