Lab
Potential Energy Lab
A marble rolls along a track whose height at each point is the potential energy U(x). Its total energy E stays fixed, so its kinetic energy is E minus U. Choose a curve and predict how many equilibria it has. Commit the prediction before the lab shows them.
Challenges
- Choose Spring well and set E to 4 J. Where are the two turning points? At x = 0, what is the kinetic energy, and what does that tell you about the speed there?
- Choose Two valleys and set E to 0 J. Then drag E down to about -0.5 J. How many separate stretches can the marble occupy at each energy, and why does the count change?
- Choose Flat stretch with walls and move the marble across the flat part. What is the force there, and what does the kinetic energy do? Why does a neutral equilibrium need a flat curve?
- Type x^3 as your equation and predict the count. Put the marble just left of 0 and then just right of 0. In both places the force points left. Why does the marble come back on one side and run away on the other?