Dictionary

momentum

Physical quantity that is equal to a body’s mass times its velocity (in special relativity: its relativistic mass times its velocity).

What makes momentum a useful quantity is that it is conserved – if several bodies interact, the sum of their momenta before and after the interaction is the same. Momentum is neither created nor destroyed, merely passed on from one body to another.

In general relativity, momentum is one of a number of quantities (like mass and energy) that acts as a source of gravity.

Definitioner

momentum

Physical quantity that is equal to a body's mass times its velocity (in special relativity: its relativistic mass times its velocity). What makes momentum a useful quantity is that it is conserved - if several bodies interact, the sum of their momenta before and after the interaction is the same. Momentum is neither created nor destroyed, merely passed on from one body to another. In general relativity, momentum is one of a number of quantities (like mass and energy) that acts as a source of gravity.

interaction

Interactions are all the different ways in which elementary or compound particles can influence each other. In elementary particle physics, "interaction" and "force" are used synonymously.

In the standard model of elementary particles, there are three fundamental interactions: electromagnetism, the strong nuclear force and the weak nuclear force. For another interaction, gravity, there is no quantum description yet.

gravity

See gravitation

gravity (gravitation)

In classical physics: An action-at-a-distance force by which all bodies that possess mass attract each other (see Newtonian theory of gravity), synonym: gravitational force. In Einstein's general theory of relativity: The fact that matter that possesses mass, energy, pressure or similar properties distorts spacetime, and that this distortion in turn influences whatever matter might be present. An introduction to the basic ideas of general relativity is provided by the section General relativity of Elementary Einstein. More information about the nature of gravity in general relativity can be found in the spotlight text Gravity: From weightlessness to curvature.

Dictionary

momentum

Further Articles

Tag Cloud