Hooke's Law
"The force needed to stretch a spring is proportional to the extension of the spring" - Robert Hooke
Stretched spring exerts pull on object holding each end:
Pull = Tension, equal/opposite to F needed to stretch,
F∝𝚫L, thus F = k𝚫L
k = spring constant (/stiffness constant), meas. in N/m
𝚫L = extension from its natural length L
Experiment - stretched spring supports weight at rest
Graph - Tension against extension, straight line thru Origin (O)
Elastic Limit - stretched beyond this, it doesn't regain its init. L
once completely unloaded.