-- There's no way to define how many of its "waves" pass a point every second.
-- Whatever you say is the speed of the pendulum, that speed can only be true at one or two points in the pendulum's swing, and it's different everywhere else in the swing.
-- The frequency of a pendulum depends only on the length of the string from which it hangs.
If you take the given information and try to apply wave motion to it:
Wave speed = (wavelength) x (frequency)
Frequency = (speed) / (wavelength) ,
you would end up with
Frequency = (30 meter/sec) / (0.35 meter) = 85.7 Hz
Have you ever seen anything that could be described as a pendulum, swinging or even wiggling back and forth 85 times every second ? ! ? That's pretty absurd.
Currently, the magnetic south pole lies about ten degrees distant from the geographic north pole, and sits in the Arctic Ocean north of Alaska. The north end on a compass therefore currently points roughly towards Alaska and not exactly towards geographic north.
