Stretch the spring and watch the shaded triangle under the force-extension line grow. That area is the elastic potential energy, half F x, which also equals half k x squared.
MissionStretch the spring, then predict how the stored energy changes when the extension is doubled.Streak 0Best 0
Doubling the extension changes the stored energy to:
extension x0.040 m
force F = kx12.0 N
energy = ½kx²0.24 J
The stored energy is the triangle area under the force-extension graph: E = half F x = half k x squared.