B Conservative and Non Conservative Forces

[Physicslearner500039]

I was referring to the conservative and non conservative forces. When i was thinking about it for example when i apply force on an object on the table the object moves a distance and when i remove the force the object does not come back to original position. Can i assume that the force i apply is non conservative?

 

[BvU]

Hi,

It's more the force you have to overcome: the friction force between the moving object and the table is the one that converts the mechanical energy to a lower grade energy (utlimately: heat).

The force you apply is neither conservative or dissipative: depends on what it is used for. For example: when placing a book on a higher shelf, the work you do is converted into gravitational potential energy.

If this brings up the question: what about placing the book on a lower shelf ? There gravity does the positive work and you do the negative work. But you still get tired. Even when just holding the book in front of you, you get tired -- and no (mechanical) work is done at all ! Tell that to your muscles !