{\displaystyle \alpha }
) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is moving. Angle of attack is the angle between the body's reference line and the oncoming flow. This article focuses on the most common application, the angle of attack of a wing or airfoil moving through air.
In aerodynamics, angle of attack specifies the angle between the chord line of the wing of a fixed-wing aircraft and the vector representing the relative motion between the aircraft and the atmosphere. Since a wing can have twist, a chord line of the whole wing may not be definable, so an alternate reference line is simply defined. Often, the chord line of the root of the wing is chosen as the reference line. Another choice is to use a horizontal line on the fuselage as the reference line (and also as the longitudinal axis). Some authors do not use an arbitrary chord line but use the zero lift axis where, by definition, zero angle of attack corresponds to zero coefficient of lift.
Some British authors have used the term angle of incidence instead of angle of attack. However, this can lead to confusion with the term riggers' angle of incidence meaning the angle between the chord of an airfoil and some fixed datum in the airplane.
I stumbled across this while doing some problems, and wanted to make sure it's true. My teacher isn't great. Physics isn't her specialty, but that's what you get at community college.
Anyways, while trying to find the critical angle at which an object will start to move, I realized that it...
This is what I did:
F_x\leq\mu_s N=\mu_s\left(mg+F\cos{\theta}\right)
...and then I would simplify. But unfortunately, I was expecting the "F"s to cancel out, meaning the force didn't matter at that critical angle. They didn't obviously. Did I set this up correctly? If not, where did I go...
In my physics lab, we have to derive an equation. The equation is for a 45, 45, 90 degree triangle. An beam of light hits the surface, then refracts. The refracted beam hits the second surface at the critical angle and refracts along the surface. Here's a crude pic of what I'm talking about...
You are standing on the edge of a pool and a person is swimming towards you under the water. Before the person is close enough to reach the critical angle of your line of sight, what would you see?
Critical angle...
Is the formula:
sin(critical angle) = 1/ mu, only true light is moving from one medium into air/ a vacuum?
Thanks in advance. :smile:
The equation relating these is :
sine(critical angle) = refractive index between 2 meterials.
Could someone please supply a proof for this?
Also, as a side question :wink: , is there a proof for the sin i / sin r = v1/ v2 , not including the one in which you draw triangles and...