Question

Why are motion that are exactly simple harmonic motion rare?

Answer 1

A Simple Harmonic motion is periodic in nature i.e. it repeate its position again and again ,and in harmonic motion Hooke's Law is applicable which states that Force is always propotional to diplacement but due to air ressistance and other factors the amplitude goes on decreasing which restricts the motion to be Simple Harmonic.That's why Simple Harmonic motion is rare in nature.