Reduced length is a quantity measured in units of length and conditionally entered to describe a physical object in certain tasks, but possibly not directly related to its size. Most often used in relation to a physical pendulum .
Physical Pendulum
In this case, the reduced length refers to the length of the mathematical pendulum , the oscillation period of which is equal to the oscillation period of the studied physical pendulum. It is calculated as
- ,
Where - moment of inertia of a given physical pendulum relative to the suspension point, - mass - the distance from the suspension point to the center of mass.
Other situations
In other areas of physics and mechanics, the meaning of the term “reduced length” has nothing to do with its meaning in the case of a pendulum. So, in relation to a liquid rocket engine , this is the ratio of the volume of the combustion chamber to the critical section to the critical section area of this chamber. The theory of resistance of materials uses the “reduced rod length” (see rod flexibility ) where - real length - a factor determined by the conditions for fixing the ends.
Literature
- Sivukhin D.V. General course of physics. - 5th edition, stereotyped. - M .: Fizmatlit , 2006. - T. I. Mechanics. - 560 s. - ISBN 5-9221-0715-1 . p. 221