Dynamics (mechanics)

The kinetics (Greek kinesis movement ) is a branch of mechanics and describes the change of motion quantities ( position, velocity and acceleration) under the action of forces in space. The kinetics is in contrast to static, which deals with the equilibrium of forces on non-accelerated bodies. Both together form the dynamics that deals with the action of forces.

This division is used primarily in engineering mechanics. In physics, however, most of the expression dynamics instead kinetics is needed. The term kinetics is not to be confused with the geometric description of the motion, the kinematics.

In the kinetics ( dynamics of the rotational movement ) is differed between the dynamics of progressive movement ( momentum of translation) and the dynamics of the rotational movement.

Kinetics is the continuation of the findings of Galileo and Newton. Galileo formulated in 1638 the law of inertia. 1687 Newton formulated his fundamental laws, which are a summary of all his experiences and conclusions from it. He wrote so that the scientific justification of the kinetics.

Important sets of kinetics

About the sets of kinetics can be the equation of motion of a system set up depending on the arbitrary generalized coordinates.

Focus set or pulse rate

Among the most famous sets of dynamics called the fundamental law of dynamics is one (also set focus or pulse rate)

In this case, the force, m is the mass and the acceleration.

This equation is valid only for a time-constant mass m. For the general case of a time-variable mass, the force needs to be defined as the derivative of the pulse with respect to time:

Thereby the speed.

Benefit rate

With the power set of mechanics and non- conservative systems can be described with one degree of freedom.

Energy theorem

The energy theorem of mechanics follows as a special case of the rate of benefit for conservative systems.

Working Set

The working set

Eventually forming the fourth way of determining the equation of motion of a dynamic system.