Elastic Potential Energy is the energy stored in an object due to the deformation caused by an external force. When the force is removed, the object returns to its original shape, and the stored energy is released. Elastic potential energy is measured in joules (J). The formula for elastic potential energy for a spring is given by,

Where:

• $U$ is the elastic potential energy,
• $k$ is the spring constant, representing the stiffness of the spring, 
• $x$ is the displacement from the equilibrium position.