phil303

How A Plane Wing Works

In fluid dynamics, there's this principle called Bernoulli's principle. Basically, it states that the pressure a fluid exerts on a body is inversely proportional to its velocity. In other words, as velocity goes up, pressure goes down.

Now, switch gears for a moment and imagine a wide, slow moving river that suddenly and quickly narrows. What happens? The water moves faster right? This is the same concept being applied to a plane wing. Think of a wing cross-section. It’s kind of flat on the bottom, and it grows fat on the top. This expansion on top juts into the air stream and effectively narrows it.

Here's the neat part. The air on top of the wing is now moving faster than on the bottom. With knowledge of Bernoulli's principle under our belt, we know that the pressure drops when the air speeds up. There’s now a different pressure on the top of the wing than what’s on the bottom, and we've just created the pressure difference we call lift! Using some

phil303

[1] (pry) main: 0> def good_star_wars_lines
[1] (pry) main: 0*  puts "something, something, something, dark slide"
[1] (pry) main: 0*  puts "something, something, something, complete"     # Crap! I typo'd dark side.
[1] (pry) main: 0*  show-input
# 1: def good_star_wars_lines
# 2: puts "something, something, something, dark slide"   
# 3: puts "something, something, something, complete"
[1] (pry) main: 0*  amend-line 2 puts "something, something, something, dark side"
[1] (pry) main: 0*  end
# => nil

phil303

[3] (pry) main: 0> def one_ring
[3] (pry) main: 0*  puts "to rule them all!"
[3] (pry) main: 0*  edit
# your editor picks up right here and shows your method thus far
[3] (pry) main: 0*  end
# => nil

phil303

[3] (pry) main: 0> def homer_says
[3] (pry) main: 0*  puts "Do'h!"
[3] (pry) main: 0*  end
# => nil
[4] (pry) main: 0> edit
# your editor shows the contents of your previous input buffer

phil303

# using our earlier homer_says method
[10] (pry) main: 0> edit-method homer_says
# into our editor of choice! Where we change "Do'h!" to something else.
[11] (pry) main: 0> homer_says
# Stupid Flanders
# => nil

phil303

[15] (pry) main: 0> cd Pry
[16] (pry) main / Pry: 1>  ls
# Pry lists out every public method or instance variable defined on the current object, which is a ton.
# Let's add a switch to clean up our results
[17] (pry) main / Pry: 1>  ls -m 
# Pry gives us only the public methods.  We can clean it up better still with grep flag.
[18] (pry) main / Pry: 1>  ls -m --grep ^co
# => Pry.methods: color color= commands commands= config config=
[19] (pry) main / Pry: 1>  cd ..
[20] (pry) main: 0>

phil303

[22] (pry) main: 0> find-method homer
# => Object
# => Object#homer_says
[23] (pry) main: 0> find-method -c "Flanders"
# => Object
# => Object#homer_says puts "Stupid Flanders"

phil303

# gist a method (-m switch) homer_says and make it public (-p switch)
[24] (pry) main: 0> gist -m homer_says -p
# => Gist created at https://gist.github.com/2721042 and added to clipboard.

phil303

class Array
  def new_count
    count = 0
    (1..self.length).each do |i|
      count += 1 if yield(self[i-1])
    end
    count
  end
end

phil303

gem 'oauth'
require 'rest_client'
require 'oauth'
require 'oauth/consumer'

# Instantiate consumer object
@consumer = OAuth::Consumer.new("mRoMvGuFliGOvCQTjSowLrEFjw8K5BbVp120jzsgRUG2D6y0Lq",
                                "ajRmJ4oWcyj9SusWAEIQLN6S400AqVgukUTEMhfvzZC7jljiA8",
                                site: "http://www.tumblr.com")