Answer:
Simple harmonic motion is difficult to generate since real processes have irreversibilities, which are omitted in the physical model and represented by physical concept of damping.
Explanation:
It is very difficult to generate simple harmonic motion since real processes have irreversibilities that dissipy the mechanical energy within the system (e.g. air viscosity, friction), meaning that a permanent presence of an external load is needed to counteract such damping effects, in contrast with simple harmonic motion, where motion is self-sustained.
