Hi there!
The period of an orbit can be found by:

T = Period (? s)
r = radius of orbit (6400000 m)
v = speed of the satellite (8000 m/s)
This is the same as the distance = vt equation. The total distance traveled by the satellite is the circumference of its circular orbit.
Let's plug in what we know and solve.

Answer:
Check the explanation
Explanation:
1) Pressure acting on the plug = Patm + P
Pressure = Patm + rho*g*h (Here h = D2)
Pressure = 101325 + 1000*9.8*7
Pressure = 169925 Pa
so, Force = PA
Force = 169925*pi*0.0152
Force = 120.1 N
B. The velocity of the second flight is negative compared to the speed.
Speed = (wavelength) x (frequency
Speed = (.020 m) x (5 / sec)
Speed = 0.1 m/s