Basics of Aerodynamics Brochure

What are forces?
Understanding forces are important in
order to understand aerodynamics.
A force is simply a push or pull that
changes an object's motion.
There are forces all around us, including
the universal forces: FRICTION (the force
of two touching objects) and GRAVITY
(attraction force that all objects with
mass have).
300 years ago, a man named Isaac
Newton made three discoveries about
forces, called Newton's Laws of Motion.
Newton's first law says that an object
that is moving will remain moving unless
a force makes it stop moving, and a
object that is not moving will not move
unless a force makes it move.
Newton's second law says that a force is
equal to the object's mass (similar to
weight) times its acceleration (its change
in speed).
AERO
DYNAMICS
...is the study of
moving air and how
things move through it
In a world without
aerodynamics...
Cars, trucks, and land vehicles
would not work
No planes, helicopters, or a
way to go into outer space
Buildings would be less stable
We would not have objects
such as sports balls, frisbees,
chimneys, and spray bottles
Newton's 3rd Law
In aerodynamics, the most
important of Newton's laws is his
3rd law, which says that each
force has an equal and
opposite reaction force.
Here is an example:
In this example, the paddle is
pushing back on the water.
Because a push is a type of force,
it can be said that the paddle is
exerting a force on the water. The
water is then exerting an equal
reaction force on the paddle in the
opposite direction, pushing the
boat forward.

What is pressure?
Pressure is force exerted over an area.
Solids, liquids, and gases (everything with
mass/weight) all exert pressure on other
objects. Air also has weight, so the 100
kilometers of air in our atmosphere is also
constantly exerting pressure on us. But,
because air is exerting pressure on us from
all directions, the pressure is balanced and
our bodies don't get crushed. The pressure
that air exerts on other objects is called air
pressure.
Air pressure is constantly affecting our lives.
The amount of air pressure that we
experience is based on our altitude, or
height. For example, at sea level, air
pressure is the highest because all of the air
molecules are pushing down on you, but at
the top of Mount Everest, air pressure is the
least because fewer air molecules are
pushing down on you.
How do planes fly? How do rockets fly?
Planes, helicopters, and other winged
aircraft use Newton's 3rd law, along with a
special property of air pressure, to fly.
That other property, called Bernoulli's
principle, says that the faster a fluid moves,
the less pressure it exerts on an object.
Airplanes' wings are designed to produce
lift, which is the upward force (push/pull)
that pushes objects upwards. Because
airplanes' wings are slanted, the air that hits
the wings is forced downward as the plane
moves, and the air exerts an equal and
opposite reaction force on the wing,
pushing it upwards. This is Newton's 3rd law
of motion.
Also, because the top of the airplane's wing
is curved, air moving over the top of the
wing has a greater speed than air moving
under the bottom, so the air moving over
the top exerts less pressure than the air
below, generating the lift force that pushes
the airplane up. This is Bernoulli's principle.
The process that rockets use to reach
outer space is a little different than that
of planes because they have to go much
faster to push past Earth's gravity and air
pressure.
Rockets mainly rely on Newton's 3rd law
and their fuel to go into outer space.
The fuel that powers rockets is made up
of liquid hydrogen and liquid oxygen.
When rockets are launched, they release
all of that fuel onto the ground with a
huge explosion. The rocket is pushing the
gases onto the ground, so as per
Newton's 3rd law, the gases will have an
equal and opposite reaction force on the
rocket, so it will push the rocket upwards
and helps it go fast enough so that it can
go into outer space.
This force that the gases push on the
rocket is called thrust.