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: The Force needed to stretch a spring is proportional to the extension of the spring ([[Hooke's Law]]). Force = Spring Constant x Extension: The '''Work Donework done''' on an object is proportional to the force and the distance traveled. Work Done = Force x Distance: The distance moved is the same as the extension 'x'.These two equations a [[Coil Spring|spring]] can be combined:: 1. <math> F = kx</math>: 2. <math> W = Fx</math>Substitute 1 into 2.:<math>W = (kx) \times x</math>found with the following equation:<math>W = kx^2</math>
:<math>W = \frac{1}{2} kx^2</math>
==Key Stage 4==