Springs and Hooke's Law
A spring's restoring force is proportional to its stretch.
About this topic
Hooke's law says the restoring force of a spring is proportional to its extension from the natural length: F = -kx, where k is the spring constant in N/m. The minus sign shows the force opposes the displacement. A stiffer spring has a larger k.
The law holds up to the elastic limit, beyond which the spring is permanently deformed and no longer returns to its original length. Springs in parallel add their constants, while springs in series are softer. A mass on a spring oscillates, and the period depends on the mass and k, not on the amplitude.
Example: a spring that stretches 5 cm under a 2 N load has k = 2/0.05 = 40 N/m, so a 6 N load stretches it 15 cm, if still within its limit. Car suspensions, mattresses, pens, trampolines, spring balances and door closers all rely on springs.
Tip: always use the extension, not the total length, and convert centimetres to metres. A common mistake is forgetting that the law fails for large stretches, and that rubber bands and many materials do not follow it.
Key ideas
- F = −kx
- k is the spring constant
- Energy stored = ½kx²
Quick check
Use cases: where Springs and Hooke's Law helps
- Homework: review the key idea behind Springs and Hooke's Law before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Springs and Hooke's Law without notes.
- Visual learning: play with the interactive lab to see how Springs and Hooke's Law changes when you adjust its inputs.
- Teaching a friend: explain Springs and Hooke's Law in your own words, then compare your version with the key ideas.
The same laws describe car crashes, sports, satellites and everyday machines.
Frequently asked questions
What is Springs and Hooke's Law?
A spring's restoring force is proportional to its stretch.
What will I learn in Springs and Hooke's Law?
F = −kx. k is the spring constant. Energy stored = ½kx².
Is Springs and Hooke's Law part of Physics?
Yes. It is one of 150 Physics topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Springs and Hooke's Law lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Springs and Hooke's Law?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.