Let’s say (not real math) that 99 mph wind cannot pick up a car, but 100 mph can. Is there a unit of strength? Or calculation for the speed vs what it can do?
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You are really only looking at wind speed, density could theoretically be a factor.
The best way of looking at it is to think “It isn’t *that* the wind is blowing, it is *what* the wind is blowing.”
The measurement you’re looking for is aerodynamic drag. This type of drag exerts a force on an object as it moves through the atmosphere. Interestingly, it does not matter if the object is moving, or if the atmosphere itself is moving. It only matters that there is a difference in speed between the two.
The amount of force exerted will consider three main factors:
1. The velocity (speed) of the air moving past the object.
2. The surface area (like the silhouette) of the object that is facing the wind.
3. The friction between the object and the air, called the coefficient of drag.
There are other factors as well, such as the atmospheric pressure and relative humidity, but these factors are very small compared to the three listed above.
There’s the “Beaufort scale” which is an empirical measure of wind force. Empirical means that the values are derived from either experiments or observations not something that’s very exact, calculated and based on specific theory.
Example 12 on the Beaufort scale is a hurricane and 3 is a gentle breeze.
you’re talking about the Beaufort scale. the Beaufort breaks windspeed into smaller bands based on the damage they can do
For designing buildings, engineers have a process for converting wind speeds to pressure on a wall.
You would measure force. If you have a gas at a certain density, moving at a certain speed, it will apply a certain force to a fixed object. The larger the surface area of the object (let’s assume a flat rectangle perpendicular to the wind), the greater the force it has to endure. Pressure remains constant, but load bearing capacity has to increase with surface area.
Point a blow dryer at a bathroom scale, it will exert a force, it just won’t be large enough to register. If you had a very sensitive bathroom scale, it would.
So if you assume a uniform density, you can gauge the forces a given wind speed will apply to a given object.
This sounds exactly like the start of a Terrance and Phillip joke.
Terrance: hey Phillip, how do you measure the strength of wind?
Phillip: I don’t know Terrance, how do you measure the strength of wind?
Terrance: ~farts~
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