Physics · Grades 9–12
Springs and the linear elastic limit · Revision sheet
Use extension, not total length, and distinguish force from stored energy.
Learn the idea
Extension
Extension is stretched length minus natural length. It may need conversion to metres.
Linear model
Within its linear elastic range, an ideal spring follows F = kx.
Energy
Stored elastic energy is one half kx squared in the same linear model.
Limits
A straight force-extension law should not be extrapolated past the stated range without evidence.
Explain without looking
- Which evidence challenges a constant-k model over a range?
- State an assumption needed before using one half kx squared.
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Independent educational review required. Grade bands are approximate; these are not officially aligned curricula.