Answer:
Horizontal and pointing south.
Explanation:
The Poynting vector points in the direction of propagation (if the wave is a sinusoidal linearly polarized plane wave of fixed frequency, as it is in our case), and it's given by (all vectors):
where points in the same direction as
, the magnetic field. This means that
must point south, because the vectorial product of a vector pointing south by a vector pointing up gives a vector pointing west. This can be deduced by the right-hand rule: if our index finger is
and our middle finger is
, then the thumb is
.
Answer:
The value is
Explanation:
From the question we are told that
The diameter of the storm is
The wind speed is
Generally the radius is mathematically represented as
=>
=>
Generally the angular velocity is mathematically represented as
=>
=>
Answer:
The pressure on the ground is about 9779.5 Pascal.
The pressure can be reduced by distributing the weight over a larger area using, for example, a thin plate with an area larger than the circular area of the barrel's bottom side. See more details further below.
Explanation:
Start with the formula for pressure
(pressure P) = (Force F) / (Area A)
In order to determine the pressure the barrel exerts on the floor area, we need the calculate the its weight first
where m is the mass of the barrel and g the gravitational acceleration. We can estimate this mass using the volume of a cylinder with radius 30 cm and height 1m, the density of the water, and the assumption that the container mass is negligible:
The density of water is 997 kg/m^3, so the mass of the barrel is:
and so the weight is
and so the pressure is
This answers the first part of the question.
The second part of the question asks for ways to reduce the above pressure without changing the amount of water. Since the pressure is directly proportional to the weight (determined by the water) and indirectly proportional to the area, changing the area offers itself here. Specifically, we could insert a thin plate (of negligible additional weight) to spread the weight of the barrel over a larger area. Alternatively, the barrel could be reshaped (if this is allowed) into one with a larger diameter (and smaller height), which would achieve a reduction of the pressure.