Wize High School Grade 12 Physics Textbook > Work and Energy
Elastic Potential Energy
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Elastic Potential Energy
- Although elastic potential energy is a form of potential energy, I like to separate it out
- As we learned earlier, according to Hooke's law:
- Springs and other compressible/expandable materials will always produce a restorative force when deformed from its equilibrium position
- Without it, we wouldn't have all the gym fail videos with elastic bands!
- That energy is stored in the form of Elastic Potential Energy = Us
k is the spring constant
Δx is the displacement relative for the equilibrium position
Watch Out!
While the formula appears to imply that elastic potential energy only applies to springs, it can really be applied to any deformable object that generates a restorative force. However, regardless of what that object is, the calculations will invariably be the same!
Practice: Friction and a Spring
A spring with a spring constant k=340 N/m is used to launch a 1.5kg block along the horizontal surface whose coefficient of sliding friction is 0.27. If the spring is compressed 18cm, how far does the block slide?
Mark Yourself Question
- Grab a piece of paper and try this problem yourself.
- When you're done, check the "I have answered this question" box below.
- View the solution and report whether you got it right or wrong.
Practice: Bungee Jumping
You have a bungee cord that extends 3.0 meters when you hang 50 kilograms of mass with it. The unstretched length is 40 meters. You want to open a bungee jumping business supporting a maximum mass of 110 kilograms. What is the absolute minimum height that you should allow for jumping (i.e. so that they don't slam into the Earth)?