(a) Period of the wave
The period of a wave is the time needed for a complete cycle of the wave to pass through a certain point.
So, if an entire cycle of the wave passes through the given location in 5.0 seconds, this means that the period is equal to 5.0 s: T=5.0 s.
(b) Frequency of the wave
The frequency of a wave is defined as

since in our problem the period is

, the frequency is

(c) Speed of the wave
The speed of a wave is given by the following relationship between frequency f and wavelength

:
Explanation:
Since I can only do this by observation, the elevation of F is approximately 850km and the elevation of B is 925km.
To solve this problem we will use the relationship given between the centripetal Force and the Force caused by the weight, with respect to the horizontal and vertical components of the total tension given.
The tension in the vertical plane will be equivalent to the centripetal force therefore

Here,
m = mass
v = Velocity
r = Radius
The tension in the horizontal plane will be subject to the action of the weight, therefore

Matching both expressions with respect to the tension we will have to


Then we have that,


Rearranging to find the velocity we have that

The value of the angle is 14.5°, the acceleration (g) is 9.8m/s^2 and the radius is



Replacing we have that


Therefore the speed of each seat is 4.492m/s