Pendulum Velocity: Understanding Wave Motion

[BeiW]

I'm a total physics noob, and as I was reading my physics textbook, I came upon this stump.

I know that for waves, V_max²=(A)(square root of k/m). Does this apply to a pendulum because its motion is wavelike?
If so, how does the spring constant k play into this when the pendulum has no spring?

 

[tiny-tim]

Welcome to PF!

Hi BeiW! Welcome to PF!

The k/m is the strength of the restoring acceleration of simple harmonic motion …

when the displacement of a spring is x, the force on it is minus kx, so (using F - ma) the acceleration is minus (k/m)x …

this applies to any simple harmonic motion … you just find the restoring acceleration, and use that instead of k/m

for a pendulum, it's g/l

(though a pendulum is only approximately a simple harmonic oscillator )