I. Momentum Theorem
Momentum theorem is a basic principle in classical mechanics, which describes that the momentum of an object will change under the action of total external force. Momentum theorem is usually expressed in the form of the following mathematical formula:
[F = \ frac { { \ Delta p } } { { \ Delta t } }]
These include:
(f) represents the total external force acting on the object (in Newton, n).
(\δp) indicates the change of momentum of an object, that is, the difference between the initial momentum and the final momentum (in kg m/s, or Newton s, n s).
(\Delta t) indicates the time interval (in seconds, s).
Second, the main points of the momentum theorem are as follows:
Conservation of momentum: if there is no external force, the momentum of an object will remain unchanged. This is part of the law of conservation of momentum.
Momentum change caused by external force: When external force acts on an object, it will change the momentum of the object. This change is related to the magnitude and direction of external force and the action time.
Units of momentum theorem: The units in momentum theorem are Newton (n) and second (s), but the units of momentum can also be expressed as kilogram meter/second (kg m/s) or Newton second (n s).
Application field of momentum theorem
1, mechanical engineering:
In mechanical engineering, momentum theorem is used to analyze and design various mechanical systems, motion devices and mechanical transmission devices. For example, it can be used to evaluate the impact and dynamic load of parts in mechanical systems and its application in mechanical vibration analysis.
2. Vehicle collision and safety:
Momentum theorem plays a key role in the study of automobile collision. By analyzing the momentum changes of vehicles before and after the collision, the speed and direction of each object in the accident can be evaluated, which is helpful to understand the process and influence of the accident.
3, sports science:
In sports science research, momentum theorem is used to analyze human movement, the design of sports equipment and sports training. For example, it can be used to study athletes' starting, throwing, jumping and other actions, as well as the influence of different equipment on athletes' momentum.