What is the difference between conservative and nonconservative force?

[Outrageous]

Conservative force like gravitational force has direction.
Non conservative force like frictional force has no direction.
so non conservative force doesn't take degree of freedom into the consideration.
Is that the meaning? please help.
Thank you

 

[WannabeNewton]

What makes you say a non-conservative force has no direction? All forces have direction. A conservative force is one for which there exists an associated potential function.

 

[Outrageous]

What makes you say a non-conservative force has no direction? All forces have direction. A conservative force is one for which there exists an associated potential function.

sorry , actually I want to say frictional force is the force that its direction can be changing all the time.
For gravity , i know we have gravitational potential energy ,this is because we define some place be zero potential and then compare potential energy of a object relative to that zero potential.
We can't do the same to the frictional force because the frictional force do not have fixed direction? how to say frictional force is not potential function?

 

[WannabeNewton]

No it has nothing to do with direction. The direction of gravity can easily change: for example a radial gravitational field has a different direction as you turn around. The point is that for conservative forces, the work done in moving from one point to another is independent of the path taken so we can construct a well-defined potential function. For friction on the other hand, the work done depends on the path so we cannot create a meaningful potential function for friction.

 

[Outrageous]

So besides look at it as a potential function , can I say that every time if the work done depends on the path then there is a non conservative force act ?
Can you please give me another example of conservative force , please.

 

[WannabeNewton]

Yes you can. Another example of a conservative force is the electrostatic force.

 

[Outrageous]

Thank you so much