Elastic potential energy

Different forms of potential energy
There are forms of potential energy other than gravitational. Potential energy exists any time a force is restrained from acting in such a way that the energy can be released if the restraint is removed. If you use the spring to launch a marble you can see how the stored potential energy of the spring is converted to kinetic energy of the marble. Compressing a spring creates potential energy because you have to do work against the force of the spring to compress it. A compressed spring stores potential energy as long as it is compressed. This type of potential energy is called elastic potential energy because it derives from the elasticity of the steel in the spring. It can be calculated by using equation (9.4). Read the text aloud
(9.4) E p = 1 2 k x 2
Ep  = elastic potential energy (J)
k  = spring constant (N/m)
x  = displacement from equilibrium (m)
Elastic potential energy
Spring uncompressed and compressed along with a calculation of the stored elastic potential energyThe quantity k in equation (9.4) is called the spring constant, which represents the strength of the restoring force exerted by the spring when it is compressed or stretched. The spring constant is a property of the spring itself and is different for every spring or other elastic material. It has units of force divided by distance, because the spring exerts a restoring force that increases as the spring is increasingly displaced (stretched or compressed) from its equilibrium position. A stiff spring resists compression or stretching, so it has a large value of the spring constant k; a loose spring has a low value of k. Read the text aloud Show Hooke’s law
Objects that store elastic potential energy share some common features: Energy is stored when the object changes its form, shape, or length; the force exerted by the elastic object acts in a direction to return it back to its original shape or position; and as it stretches or compresses more, it stores more energy. Read the text aloud Show Elastic PE and your muscles
Objects with elastic potential energy
Show Other objects with elastic PE
Which has a greater spring constant value, a Slinky® or a car’s suspension spring? Show

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