State that extension is directly proportional to force up to the limit of proportionality.

In the subtopic Hooke's law and spring constant, this learning objective focuses on state that extension is directly proportional to force up to the limit of proportionality. For AQA GCSE Physics 8463 Unit 4.5 Forces, keep the explanation inside Hooke's law and spring constant and Forces and elasticity. Approved keywords for this objective include force, extension, and limit of proportionality. A strong answer separates scalar and vector quantities, uses correct units where quantities are involved, and links the physical reasoning back to state that extension is directly proportional to force up to the limit of proportionality. This is not a generic revision point: it is specifically about Hooke's law and spring constant, Forces and elasticity, and the approved wording of the learning objective.