1. Work and Energy Partial Derivatives

2. Work The force can be three dimensional.

3. Force and Potential Energy Force is the negative of the slope of the potential energy versus position graph.

4. Force in 3D Gradient of U

5. Problem 1 An electrically charged particle is held at rest at the point x=0, while a second particle with an equal charge is free to move along the positive x- axis. The potential energy of the system is as follows where C is a positive constant that depends on the magnitude of the charges. Derive an expression for the x-component of force acting on the movable charge, as a function of it position

6. Potential Energy for Problem 1

7. Problem 2 A puck slides on a level, frictionless air-hockey table. The coordinates of the puck are x and y. It is acted on by a conservative force described by the potential-energy function that follows. Derive an expression for the force acting on the puck.