A central force acting on an object is one whose magnitude depends only on the scalar distance r of the object from the origin and whose direction is along the position vector from the origin to the object. In physics, force is that which changes or tend to change the state of rest or motion of a body. ... The term scalar is used in mathematics, physics, and computing basically for quantities that are characterized by a single numeric value and/or do not involve the concept of direction. ... In mathematics, the origin of a coordinate system is the point where the axes of the system intersect. ...

This has some important consequences. The energy of the object is conserved in time. Because of this last property, a central force field is an example of a conservative field. Since a central force is always parallel to the object's position vector, the torque exerted by a central force on the object is zero. As a result, the angular momentum of an object in a central force field is constant, and the motion of the object takes place in a plane perpendicular to the angular momentum. In vector calculus, an irrotational or conservative vector field is a vector field whose curl is zero. ... In physics, torque can be thought of informally as rotational force. The SI units for Torque are newton meters although centinewton meters (cN·m), foot-pounds force (ft·lbf), inch pounds (lbf·in) and inch ounces (ozf·in) are also frequently used expressions of torque. ... Gyroscope. ...

Properties

A central force can always be expressed as the negative gradient of a potential: In the above two images, the scalar field is in black and white, black representing higher values, and its corresponding gradient is represented by blue arrows. ... It has been suggested that this article or section be merged with Scalar potential. ...

As a consequence the curl of a central field is zero: This article is about the cURL command line tool. ...

An object in a central force field obeys Kepler's second law due to conservation of angular momentum. Johannes Keplers primary contributions to astronomy/astrophysics were his three laws of planetary motion. ... In physics, a conservation law states that a particular measurable property of an isolated physical system does not change as the system evolves. ...

Examples

Gravitational force and Coulomb force are two familiar examples with F(r) being proportional to 1/r². This article covers the physics of gravitation. ... In physics, Coulombs law is an inverse-square law indicating the magnitude and direction of electrical force that one stationary, electrically charged substance of small volume (ideally, a point source) exerts on another. ...