# Meaning of “Simple” in Simple Pendulum and Simple Harmonic Motion?

I have gone through the Phys.SE question Can a simple pendulum be considered a simple harmonic oscillator?. From the 1st answer of this Question it seems to me that another type of "Harmonic motion" is "Damped Harmonic Motion".

But can you please explain what the other type of Pendulum is? Is this Compound pendulum or Damped Pendulum or Something else?

• For a damped pendulum, you just introduce a term $\gamma \dot{\theta}$ into the equations of motion. – JamalS May 22 '14 at 5:41
• Simple pendulum can mean simple compared to compound, or simple compared to one that behaves like a simple pendulum despite large amplitude. Recall the simple pendulum analysis makes assumptions about small motions and very small angle. Check on "isochronous pendulum". – C. Towne Springer May 22 '14 at 5:43
• @ C. Towne Springer , see this wikipedia article, here there is no assumption of small swing , but they still write simple pendulum:en.wikipedia.org/wiki/… – user22180 May 22 '14 at 5:53

The simple pendulum (see wikipedia or hyperphysics) leads to a simple differential equation by using Newton's second law: $$\ddot{\theta}+\frac{g}{l}\sin(\theta)=0.$$