I think it's B hope it helps
To solve this problem we will apply the concepts related to pressure, depending on the product between the density of the fluid, the gravity and the depth / height at which it is located.
For mercury, density, gravity and height are defined as



For the air the defined properties would be



We have for equilibrium that


Replacing,

Rearranging to find 


Therefore the elevation of the mountain top is 9400ft
Answer:
740 N
Explanation:
We are given that
Radius,r=0.3 m
Torque,
We have to find the magnitude of the static frictional force.
According to question
Torque by engine=Torque by static friction




Hence, the magnitude of static frictional force=740 N
I think you are asking if fm radio waves follow a wave motion and if so, the answer is yes