What is Hooke's law? In this video, Professor Walter Lewin presents Hooke's law. Hooke's Law is a principle in physics stating that the force (F) needed to stretch or compress an elastic object (like a spring) is directly proportional to the distance (x) it's stretched or compressed from its resting position, expressed as F = k x, where k is the spring constant (stiffness). This relation holds within the material's elastic limit, meaning the object returns to its original shape after the force i