Line of action
In technical mechanics, the line of action or line of action is the straight line that indicates the position of a force in space. Together with the sense of direction , it gives the direction. A force vector can be described by specifying the amount, the direction and the point of application .
According to the well-known axiom of displacement of statics, a force on a rigid body can be displaced along its line of action without the effect of the force on this body changing. This property is also known as line volatility. Therefore it is possible to neglect the exact point of attack for some problems in technical mechanics.
The volatility of lines is only given for rigid bodies: A change in the point of attack on a body made of rubber , for example, would deform the body differently each time. However, the effect of the force on the body is different.
The action force known from the principle of interaction and the associated reaction force lie on a line of action. However, their points of attack are always found on different bodies.
The concept of the line of action serves to differentiate between general and central systems of forces . In central systems of forces, the lines of action of all forces in the system intersect at one point, so that rotational degrees of freedom and torques do not have to be taken into account.
A pair of forces is a pair of equally large, but oppositely directed forces that do not lie on the same line of action. It creates a torque on a body .
Individual evidence
- ↑ James Allen: Statics for mechanical engineers for dummies . John Wiley & Sons, ISBN 3-527-70761-1 , pp. 58 ( limited preview in Google Book search).
- ↑ Bruno Assmann, Peter Selke: Technical Mechanics 1 . Oldenbourg Wissenschaftsverlag, Munich 2010, ISBN 978-3-486-59133-0 .
- ↑ a b c Bernd Markert : Mechanics 1 Stereostatics. Statics of rigid bodies. Institute for General Mechanics , Aachen 2014.