88.2 Conservative force and the potential energy 1. What is conservative force If a work done by the force on any system as it moves between two points is independent of the path following by the system between the two points or if the work done by the force on any system around any closed path is zero. Then the force is called conservative force a(2) FF.dr=0 (b) 88.2 Conservative force and the potential energy If{F·dr≠0, then the force is called nonconservative force IffF.dr=0, then the force is called zero-work force 2. Some examples of conservative forces local gravitational force F=-mgj --a constant force W=F·△F 1010 §8.2 Conservative force and the potential energy 1. What is conservative force If a work done by the force on any system as it moves between two points is independent of the path following by the system between the two points; or if the work done by the force on any system around any closed path is zero. Then the force is called conservative force. ⋅d = 0 ∫ F r r r ∫ ∫ ⋅ = ⋅ b a b a F r F r (1) (2) d d r r r r b ⋅d ≠ 0 ∫ F r r r If , then the force is called nonconservative force. If , then the force is called zero-work force. ⋅d = 0 ∫ F r r r 2. Some examples of conservative forces 1local gravitational force W F r r r = ⋅ ∆ F mgj ˆ = − r --a constant force §8.2 Conservative force and the potential energy