You've given the answer, right there in your question.
The "magnitude of gravity" is described in terms of the acceleration
due to it, and you just told us what that is.
We can also notice that the figure you gave is about 0.66 of the
acceleration due to gravity on the Earth's surface. That tells us that
the distance from the Earth's center at that height is about
(1 / √0.66) = 1.23 times
the Earth's radius, so the height is about 910 miles above the surface.
Wavelength = (speed) / (frequency)
= (3 x 10⁸ m/s) / (1 x 10⁸ /s) = 3 meters
Harmonics, Loop and Harmonic number
Hope this helps :)
The wall will push back, in exactly the opposite direction, and with
exactly the same size force.
That's why the net force on the palm of your hand is zero, and that
in turn is the reason that your hand doesn't accelerate.
If you keep increasing the strength of your push, then eventually you
exceed the force that the wall is capable of delivering. Then the wall
crumbles and falls, your hand accelerates in the direction you're pushing,
and the crowd goes wild !