Changes

==Key Stage 4==

===Meaning===

The '''elastic potential energy store''' is an [[Energy Store|energy store]] associated with stretched, squashed and twisted elastic [[object]]s.

: The '''elastic potential energy store''' of an [[object]] is related to two [[property|properties]] of the [[object]]:

*The [[Spring Constant]] of the [[object]]. - The amount of [[force]] needed to stretch or squash it's shape by a given distance. The greater the [[Spring Constant|spring constant]] the greater the '''elastic potential energy''' stored.

===Equation===

k = The [[Spring Constant|spring constant]] of the [[object]].

===Calculating Elastic Potential Energy===

{| class="wikitable"

| style="height:20px; width:200px; text-align:center;" |A bow with a spring constant of 400N/m is stretched 0.5m with a force of 200N. Calculate the elastic potential store of the bow.

Final Length = 9.1m

x = Final Length - Original Length = 9.1 - 0.1 = 9.0m

|-

<math>E_e = \frac{1}{2} k x^2</math>

<math>E_e = 50J</math>

<math>E_e = \frac{1}{2} k x^2</math>

<math>E_e \approx 20,000J</math>

<math>E_e = \frac{1}{2} k x^2</math>

<math>E_e \approx 32J</math>

|}