Ready in the left valley
Drag to orbit
Surface height represents potential energy U. The white particle speeds up downhill and slows down uphill.
Energy conservation laboratory
3D EnergyLandscape
Roll a particle through an energy landscape. Watch potential and kinetic energy trade places while their total stays fixed.
1Predict2Launch3Track energy
Can it cross the barrier?
The central saddle is 0.75 J high. Compare that barrier with the particle's total energy.
Initial kinetic energyThe launch energy in the left valley
PredictionWill the particle reach the right valley?
Choose before launchingUse the total-energy plane as a clue.
Show total-energy planeAccessible regions satisfy U ≤ E
Kinetic K0.45 J
Potential U0.02 J
Total E0.47 J
Saddle barrier0.75 J
Below the saddleThe particle will turn around before the centre.
Height is potential
Valleys are stable low-energy regions. Hills and saddles are energy barriers.
Energy changes form
Climbing converts kinetic energy into potential energy; descending reverses the exchange.
E = K + U = constant
Force points downhill
The steepest decrease of the energy surface determines the force direction.
F = −∇U
Challenge
Ask about energy →Find the smallest launch energy that reaches the other valley.
Move the slider in small steps and compare total energy with the 0.75 J saddle.