About this experiment
Hang a mass from an ideal spring and measure how far it extends. Record a sequence of force-extension points, then change the spring stiffness to compare slopes. The spring drawing shows equilibrium positions, not the motion while a mass settles.
Learning goals
- Relate hanging weight to spring extension at equilibrium
- Determine spring stiffness from the slope of a force-extension graph
- Calculate the energy stored in an extended spring
How to use it
- 1Keep stiffness at 20 N/m. Start with zero mass and record the point.
- 2Increase mass to 0.50, 1.00 and 1.50 kg, recording each force and extension.
- 3Calculate force divided by extension for each nonzero point. Compare it with the selected stiffness.
- 4Keep the recorded points, increase stiffness and compare the new line with the original measurements.
The model
Assumptions
- The spring is massless and obeys a linear force law for every extension shown. Real springs have a limited elastic range.
- Each displayed state is static equilibrium; oscillations and damping are not simulated.
- The hanging mass is a point load and gravity is uniform at 9.8 N/kg.
Try this in class
- Q1What extension should a 1 kg mass produce when stiffness is 20 N/m?
- Q2If stiffness doubles at a fixed mass, what happens to extension and stored energy?
- Q3How could a curved experimental force-extension graph reveal the limits of this model?
Frequently asked questions
Does a stiffer spring give a steeper graph?
Yes. Force is plotted vertically and extension horizontally, so the slope is stiffness k in N/m.
Why can the simulated spring stretch so far?
This is an ideal linear model with no elastic limit. A real spring may deform permanently or break before reaching large extensions.