Definition
A principle of physics stating that within the elastic limit of a material, the amount of deformation (stretch, compression, or bend) is directly proportional to the force applied. Doubling the force doubles the deformation, provided the material is not stressed beyond the point where it can return to its original shape.
Plain English
How much something stretches or squashes is in direct proportion to how hard you push or pull on it — as long as you don't push or pull hard enough to permanently bend or break it.
Context Anchor
Seen in aircraft structures, control-system springs, landing gear springs, and basic discussions of material strength.
Derivation
Named after Robert Hooke, the 17th-century English scientist who first described the relationship in 1660. He summarised it in the Latin phrase 'ut tensio, sic vis' — 'as the extension, so the force.' Knowing it carries his name simply explains why the term has an apostrophe-s and isn't a technical acronym.
Why Pilots Care
Aircraft structures, springs in instruments, and many control system components rely on Hooke's Law to behave predictably. When a part is loaded beyond its elastic limit, Hooke's Law no longer applies and the part is permanently deformed — which is why overstressing an airframe or a spring can cause hidden damage even if it appears to spring back.
Analogy
Think of gently pulling a spring. A small pull gives a small stretch, and a bigger pull gives a bigger stretch. Pull too hard, and the spring may not return to its original length.
Grounding Statement
Pull a spring twice as hard and it stretches twice as far — until you pull hard enough to ruin it.
Intuition Check
Hooke's Law is not an aviation regulation or legal rule. Here, "law" means a reliable physics relationship between applied force and the amount a material flexes.
Example Sentence 1
The landing gear oleo strut compresses in accordance with Hooke's Law during a normal touchdown, returning to its original length once the load is removed.
Example Sentence 2
Maintenance crews rely on Hooke's Law to confirm that shock-absorber springs still return to their original length after repeated landings.