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WHAT HAVE WE SEEN SO FAR?. A brief recap…. FLUIDS. So far, we have looked at fluids and we have seen that fluids exist as both liquid and as air. . We have also seen how a fluid passes around an object. BERNOULLI’S PRINCIPLE. - PowerPoint PPT Presentation
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WHAT HAVE WE SEEN SO FAR?
A brief recap…
So far, we have looked at fluids and we have seen that fluids exist as both
liquid and as air.
FLUIDS
We have also seen how a fluid passes around an object.
Bernoulli noticed that pressure exists all around us. In fact, he found that
stationary fluids such as air and water exert pressure in
all directions.
BERNOULLI’S PRINCIPLE
Bernoulli also discovered that the faster air flows, the
less pressure it has.
Now, we are going to look at the force of LIFT and see
how it applies to flying objects such as airplanes.
FLYING WINGS
Airplanes stay in the air because of the shape of
their wings.
Imagine a wing without it’s
skin on
Imagine a wing flying fast through the
air
DIRECTION OF AIRPLANE
The special shape of a wing is called an airfoil.
An airfoil is flat on the bottom and curved on
the top.
BOTTOM
TOP
TOP
BOTTOM
DIRECTION OF AIRPLANE
How does a wing rise as air passes around it?
When air hits the front of the wing it splits up
When air hits the front of the wing it splits up
When air hits the front of the wing it splits up
When air hits the front of the wing it splits up
When air hits the front of the wing it splits up
When air hits the front of the wing it splits up
When air hits the front of the wing it splits up
When air hits the front of the wing it splits up
When air hits the front of the wing it splits up
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
The air flowing over the curved top of the wing has further to go than the air
going under the flat bottom of the wing.
Predict: How will both air molecules arrive at the tail of the wing at the
same time if the molecule on top has a farther distance to travel?
For the two streams of air to reach the back of the wing at the same time, the top stream must travel faster than the bottom. (It has a farther distance to
go.)
For the two streams of air to reach the back of the wing at the same time, the top stream must travel faster than the
bottom. (It has a farther distance to go.)
For the two streams of air to reach the back of the wing at the same time, the top stream must travel faster than the
bottom. (It has a farther distance to go.)
This fast moving air creates a low pressure area on the top of the wing
and a high pressure area on the bottom of the wing. (Bernoulli’s
Principle)
LOW PRESSURE
HIGH PRESSURE
Predict: What is our high pressure air zone going to do?
Why?
LOW PRESSURE
HIGH PRESSURE
Air will move from a high pressure zone to low pressure zone. As it pushes against the wing, lift is
created.
LOW PRESSURE
HIGH PRESSURE
UP
UP
UP
AND
AWAY!!!
