when the spring stops oscillating, the final Gravitational Potential Energy is less than the starting PE of the spring, all while the Total Energy before and after remain the same. Why is this so?

Question

when the spring stops oscillating, the final Gravitational Potential Energy is less than the starting PE of the spring, all while the Total Energy before and after remain the same.  Why is this so?

Vocaloid · Answer

In theory the PE should remain constant before and after the spring starts and stops oscillating, but in reality you lose a tiny amount due to friction/heat/sound