- #1
Soren4
- 128
- 2
I do not understand the reason why a conservative force always "tries" to reduce the potential energy of a system at its minimum (forgive me if I said it in a wrong way).
The explanation I gave me is: since for a conservative force, from the definition of potential energy, [itex]W=-\Delta U[/itex] that means that if the work is positive, the potential energy decreases. Now, saying "the work is positive" means that the force is not opposing the displacement (more precisely [itex]\vec{F} \cdot \vec{ds}>0 [/itex]) or equivalently that the kinetic energy is increasing. Nevertheless I do not see why a (conservative) force should "naturally" do positive work (since this depends also on [itex]\vec{ds}>0 [/itex]). This is surely a wrong explanation.
So what is the correct reason for this? And how to interpret this fact?
The explanation I gave me is: since for a conservative force, from the definition of potential energy, [itex]W=-\Delta U[/itex] that means that if the work is positive, the potential energy decreases. Now, saying "the work is positive" means that the force is not opposing the displacement (more precisely [itex]\vec{F} \cdot \vec{ds}>0 [/itex]) or equivalently that the kinetic energy is increasing. Nevertheless I do not see why a (conservative) force should "naturally" do positive work (since this depends also on [itex]\vec{ds}>0 [/itex]). This is surely a wrong explanation.
So what is the correct reason for this? And how to interpret this fact?