The activity models a horizontal spring and cart without friction. As the cart approaches equilibrium, stored elastic energy becomes kinetic energy. Near either extreme, speed falls to zero and stored spring energy is greatest. Change mass and stiffness independently to compare the oscillation period rather than assuming every spring ticks at one rate.
Forces, motion and energy · Discover & try
Why does a stretched spring pull back?
Reading level 3 of 5 · IndependentChange
Word help
Equilibrium
The position where the ideal spring exerts zero restoring force.
Stiffness
The spring factor k, measured in newtons per metre.
Elastic energy
Energy stored when the spring is displaced.
Watch · Try · Explain
See how it works
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Ideal linear, massless spring and frictionless horizontal cart, within the elastic range.
What to look for
- Compare restoring force on opposite sides.
- Watch the cart cross equilibrium at nonzero speed.
- Change stiffness while keeping mass fixed.
Explain what you noticed
A separate ideal spring has stiffness 30 N/m and is displaced 0.2 m to the right. What spring force acts on its cart?
Keep this idea: Within its elastic range, an ideal spring’s restoring force points toward equilibrium and grows with displacement.
Follow the sources
- OpenStax, Rice University — Hooke’s Law: Stress and Strain Revisited
- OpenStax, Rice University — Common Forces
Source material checked 2026-10-28. Explanations and activities by Nepedia. Source links do not imply endorsement.
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