How does kinetic energy differ from momentum?


In addition to energy, there is another important variable that is retained in all physical processes. This size is called pulse. The conservation of momentum depends on the Symmetry of space Together.

Similar to that kinetic energy the momentum of an object also depends on the speed and the mass. However, the dependence of the momentum on the speed is not as great as that of the energy. For speeds that are significantly lower than the speed of light, an object only has twice the momentum at twice the speed.

The word pulse

In non-physical usage, the word "impulse" rather stands for a brief impact, e.g. a blow with a hammer. In fact, this is also the origin of the physical term. If you hit a metal ball with a hammer, it will get it rolling and the impulse given once remains (apart from friction).

The connection between a time-limited impulse and the measured variable impulse is established by defining the impulse as force times time. A certain force that acts over a given time transmits the impulse that is calculated as the product of force and time. The kinetic energy, on the other hand, is defined by the work as force times distance.


If two balls collide on a billiard table, both the entire kinetic energy and the common momentum of the two balls are retained. From these two Conservation Laws one can clearly predict the impact process.


There is another difference between energy and momentum: while energy is a measured quantity that can be specified by a simple number with a unit, momentum is directional. It must be indicated by numerical value and direction. Such quantities are mathematically called Vectors shown.

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Last change: 02/09/2006