❌The Bernoulli Principle Flashcards
What is the Bernoulli principle?
Where air molecules exert less pressure the faster they travel and more pressure when they travel slower.
What is a lift force?
Causes a body to move perpendicular to the direction to travel.
What can a lift force do?
Enables the object (e.g. discus) to stay in the air for longer, therefore increasing the horizontal distance it travels.
How is lift achieved?
When different air pressures act on an object.
What’s the pressure like the faster/slower the air travels?
Faster = lower pressure Slower = higher pressure
What is the angle of attack?
The tilt of a projectile relative to the air flow.
What does the angle of attack do?
It changes the flow of air around the discus so the air that travels over the top of the discus has to travel a longer distance than the air underneath.
This results in the air above the discus travelling at a faster velocity, which therefore creates a lower pressure.
This lower pressure above the discus creates an upward lift force and allows the discus to stay in the air for longer, resulting in a greater horizontal distance.
What happens if the angle of attack is too great?
Then lift is reduced and drag increases, causing the discus to stall.
What’s the optimum angle of attack for the discus?
It produces the best lift for the discus is anything between 25 and 40.
What direction does the lift force work?
Upwards lift force.
Downwards lift force.
What uses the downwards lift force?
Skiers
Cyclists
Racing cars
Why is downwards lift force needed?
Needs to be pushed down into the ground so a greater friction force is created.
What’s an example of downward lift force?
In a formula 1 sports car, the spoiler is angled so the lift force can act in a downward direction to push the car into the track.
This happens because the air travels over the top of the car a shorter distance than the air underneath, due to the angle of the spoiler.
As a result, the air above the car travels at a slower velocity and at a higher pressure.
This creates a greater friction force so the types maintain a firm grip on the track as the car travels at high speed and around corners.
How do cyclists have a downwards force?
The low streamlined body position over the handlebars means that the air that travels over the top of the cyclist has to travel a shorter distance than the air underneath.
This results in the air above the cyclist travelling at a slower velocity which therefore creates a higher pressure.
This higher pressure above the cyclist creates a downward lift force and allows the tyres of the bike to maintain a firm grip on the track.
