# What is the difference between conservative and nonconservative force?

1. May 21, 2013

### Outrageous

Conservative force like gravitational force has direction.
Non conservative force like frictional force has no direction.
so non conservative force doesnt take degree of freedom into the consideration.
Thank you

2. May 21, 2013

### 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.

3. May 21, 2013

### Outrageous

sorry , actually I wanna 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 cant 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?

4. May 21, 2013

### 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.

5. May 21, 2013

### 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.

6. May 21, 2013

### WannabeNewton

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

7. May 21, 2013

### Outrageous

Thank you so much