1. Hooke’s Law

2. English physicist Robert Hooke (1678) discovered the relationship b/t the hooked mass-spring system’s force and displacement. F elastic = - kx F = elastic (restoring) force k = spring constant of proportionality (N/m) x = elongation from equilibrium ***the negative sign indicates that the direction of elongation(x) is always opposite to the restoring force

3. Hooke’s Law k = F/x can be found by manipulation and graphing: Fslope = F/x =k x the relation is linear direct if the elastic limit is not exceeded.

4. Hooke’s Law Elastic Limit – the point at which an additional small applied force is great enough to permanently stretch the spring At this point, the graph changes from a proportional linear relation to a non-proportional one. k= spring constant – a measure of the stiffness of a spring (units: N/m) A greater k value, the stiffer the spring b/c a greater force is needed to stretch it

5. Hooke’s Law & Simple Harmonic Motion SHM – simple harmonic motion- vibration about an equilibrium position in which a restoring force is proportional to the displacement from equilibrium Restoring force – force that pushes or pulls a mass back towards its equilibrium position Any periodic motion that is the result of a restoring force that is proportional to the displacement is described by SHM