CogKnoSys

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Physical

Potential Energy

Potential energy is stored energy that an object or system has because of its position or the arrangement of its parts.

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The idea

Potential energy is stored energy that an object has because of its position or the arrangement of its particles. A book on a high shelf, a stretched rubber band and a drawn bow all hold potential energy. The energy stays stored until something releases it, such as a fall or a snap back.

Lifting a ball or stretching a spring takes work against a force such as gravity. That work is not lost, because it is stored as potential energy. When the object is let go, the force does the work back, so the ball falls or the spring returns to its starting shape. For a lifted object, the stored energy equals its weight multiplied by the height it was raised.

There are several types of potential energy, and each one is tied to a particular force. Common types include gravitational potential energy, the elastic energy of a stretched spring and the electric potential energy of charges. Chemical potential energy depends on how atoms or molecules are arranged, which is why fuels and food store energy. Roller coasters use chains to haul cars up a slope, building up potential energy that turns into speed as the cars drop.

Check yourself

Question 1 of 3

Who coined the term potential energy?

Pick one. The first pick counts.

Composition

what it's made of

  • Position — Where an object sits compared with other objects, such as how high it is above the ground.
  • Configuration — The arrangement of an object's particles, such as atoms joined in a molecule.
  • Restoring force — A force, such as gravity or a spring's pull, that the stored energy works against.
  • Reference position — Potential energy is measured as a difference from a chosen starting point.
  • Joule — The SI unit used to measure potential energy.

Connection

how it relates

Under Energy Forms

Related

  1. Gravitystrength 80 of 100

    Gravity gives a raised object gravitational potential energy, which it pays back when the object falls.

  2. Frictionstrength 50 of 100

    Friction wastes some energy each time stored potential energy is turned back into motion.

  3. Water Cyclestrength 50 of 100

    Water vapor lifted high into the sky gains potential energy that returns when rain falls and rivers run downhill.

  4. Muscle Contractionstrength 40 of 100

    Muscles draw on chemical potential energy stored in food to power each contraction.

Change

how and why it evolves

Past
The Scottish engineer and physicist William Rankine coined the term potential energy in 1853. In 1867, Rankine described it as energy of configuration, in contrast to the energy of activity.
Now
Today, pumped-storage plants pump water up to a higher lake and let it flow back down through generator turbines at times of peak demand.
Next
Systems that store electricity by raising rail cars to higher ground will likely be tested further as power grids need more storage.

Knowledge you can walk. Read the idea, then step up, across or down.

Potential Energy

Potential energy is stored energy that an object or system has because of its position or the arrangement of its parts.

Learn, discuss, create, buy or invest

The idea

Potential energy is stored energy that an object has because of its position or the arrangement of its particles. A book on a high shelf, a stretched rubber band and a drawn bow all hold potential energy. The energy stays stored until something releases it, such as a fall or a snap back.

Lifting a ball or stretching a spring takes work against a force such as gravity. That work is not lost, because it is stored as potential energy. When the object is let go, the force does the work back, so the ball falls or the spring returns to its starting shape. For a lifted object, the stored energy equals its weight multiplied by the height it was raised.

There are several types of potential energy, and each one is tied to a particular force. Common types include gravitational potential energy, the elastic energy of a stretched spring and the electric potential energy of charges. Chemical potential energy depends on how atoms or molecules are arranged, which is why fuels and food store energy. Roller coasters use chains to haul cars up a slope, building up potential energy that turns into speed as the cars drop.

Check yourself

3 quick questions, instant feedback.