请输入您要查询的百科知识:

 

词条 Scleronomous
释义

  1. Application

  2. Example: pendulum

  3. See also

  4. References

A mechanical system is scleronomous if the equations of constraints do not contain the time as an explicit variable and the equation of constraints can be described by generalized coordinates. Such constraints are called scleronomic constraints. The opposite of scleronomous is rheonomous.

Application

{{main|Generalized velocity}}

In 3-D space, a particle with mass , velocity has kinetic energy

Velocity is the derivative of position with respect to time . Use chain rule for several variables:

where are generalized coordinates.

Therefore,

Rearranging the terms carefully,[1]

where , , are respectively homogeneous functions of degree 0, 1, and 2 in generalized velocities. If this system is scleronomous, then the position does not depend explicitly with time:

Therefore, only term does not vanish:

Kinetic energy is a homogeneous function of degree 2 in generalized velocities .

Example: pendulum

As shown at right, a simple pendulum is a system composed of a weight and a string. The string is attached at the top end to a pivot and at the bottom end to a weight. Being inextensible, the string’s length is a constant. Therefore, this system is scleronomous; it obeys scleronomic constraint

where is the position of the weight and is length of the string.

Take a more complicated example. Refer to the next figure at right, Assume the top end of the string is attached to a pivot point undergoing a simple harmonic motion

where is amplitude, is angular frequency, and is time.

Although the top end of the string is not fixed, the length of this inextensible string is still a constant. The distance between the top end and the weight must stay the same. Therefore, this system is rheonomous as it obeys constraint explicitly dependent on time

See also

  • Lagrangian mechanics
  • Holonomic system
  • Nonholonomic system
  • Rheonomous
  • Mass matrix

References

1. ^{{cite book |last=Goldstein|first=Herbert|title=Classical Mechanics|year=1980| location=United States of America | publisher=Addison Wesley| edition= 3rd| isbn=0-201-65702-3 | page=25}}
Skleronom

3 : Mechanics|Classical mechanics|Lagrangian mechanics

随便看

 

开放百科全书收录14589846条英语、德语、日语等多语种百科知识,基本涵盖了大多数领域的百科知识,是一部内容自由、开放的电子版国际百科全书。

 

Copyright © 2023 OENC.NET All Rights Reserved
京ICP备2021023879号 更新时间:2024/9/23 15:24:10