Elastic potential energy

E=\tfrac12 k x^2

Result unit: J (joule)

What it describes

The energy stored in a stretched or compressed spring.

E

elastic potential energy

[J]

k

spring constant

[N/m]

x

deformation (displacement from equilibrium)

[m]

The energy stored in a deformed spring grows with the square of the deformation. When released, it is converted into kinetic energy (catapult, bow).

Springs and oscillations. The work needed to deform the spring equals this energy.

A spring with constant

k=200

N/m is compressed by 0.1 m. Find the stored energy.

Substitution

k=200

N/m,

x=0.1

Result

E=\tfrac12\cdot200\cdot0.1^2=1

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