Speed of airflow to lift a man

In summary: So he was moving at about 49 mph in a downwards direction and the net force on his body was about 24 lbs.
  • #1
Suyash Singh
168
1
mass of air X velocity = mass of man x gravity
(10000)x(v)=60x10
velocity=600/10000
how come velocity is so less?
I am still in school so forgive me if my calculations look stupid.
 
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  • #2
Suyash Singh said:
mass of air X velocity = mass of man x gravity
(10000)x(v)=60x10
velocity=600/10000
how come velocity is so less?
I am still in school so forgive me if my calculations look stupid.
It depends on the size of the wing... :smile:
 
  • #3
Or do you mean like indoor skydiving?

https://www.iflyworld.com/

https://www.tmtmtour.com/wp-content/uploads/2018/01/ifly2.jpg
ifly2.jpg
 

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  • #4
berkeman said:
Or do you mean like indoor skydiving?

https://www.iflyworld.com/

https://www.tmtmtour.com/wp-content/uploads/2018/01/ifly2.jpg
View attachment 225341
i was talking about thunderstorm
there is a storm coming to Delhi with speed 60 kmph.
I was thinking if people would start flying. Or maybe the small dogs on street.
 
  • #5
Suyash Singh said:
i was talking about thunderstorm
there is a storm coming to Delhi with speed 60 kmph.
I was thinking if people would start flying. Or maybe the small dogs on street.
Looks like 60-80mph is pretty close to the limit...

https://i.ytimg.com/vi/ITBq82c6RzY/maxresdefault.jpg

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  • #6
It seems that nobody has really addressed your attempt at calculation. Where did you obtain that formula from, and also what made you chose 10,000kg as your mass of air?
 
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  • #7
cjl said:
It seems that nobody has really addressed your attempt at calculation. Where did you obtain that formula from, and also what made you chose 10,000kg as your mass of air?
I thought that
momentum of air= force on man by earth
also mass of air per square metre=10000kg
 
  • #8
cjl said:
It seems that nobody has really addressed your attempt at calculation
Hey, who you calling "nobody"?! :biggrin:
 
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  • #9
berkeman said:
Hey, who you calling "nobody"?! :biggrin:
I meant directly addressing the calculation rather than the end result. You did address a number of the factors though
 
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  • #10
Suyash Singh said:
I thought that
momentum of air= force on man by earth
also mass of air per square metre=10000kg
Momentum isn't the worst place to start here, but I'll address that more after we look at the mass some more. 10,000 kg is about right if you're looking at the entire column of air from the ground up to space, but what bearing would that have on its ability to lift a person? If a person is standing in the wind, what mass of air actually interacts with them?
 
  • #11
Suyash Singh said:
I thought that
momentum of air= force on man by earth
On that track you will find out what happens when you hit somebody with 10 tons of air in one go. (But the equation is still wrong.)

What you really need is indeed the "force on man by earth", but what balances it is the air resistance (try look it up).
 
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  • #12
Rive said:
On that track you will find out what happens when you hit somebody with 10 tons of air in one go. (But the equation is still wrong.)

What you really need is indeed the "force on man by earth", but what balances it is the air resistance (try look it up).
conservation of momentum
2 x mass of air x velocity (since air velocity won't change)=m(0)+ m(v)
2x 10000 x velocity=60v
 
  • #13
Suyash Singh said:
conservation of momentum
That's an excellent tool for collisions, for example: but for this, you better to swim instead.
 
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  • #14
My grandson "flew" in one of those iFLY vertical wind tunnels and he and his adult "instructor" where suspended with a air velocity of about 100 mph. The force of wind applied perpendicularly on a one sq foot surface is about 49 lbs.
 
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1. How does the speed of airflow affect lift for a man?

The speed of airflow is directly correlated to the amount of lift that can be generated for a man. As the speed of airflow increases, the lift force also increases. This is due to the Bernoulli's principle, which states that the pressure of a fluid decreases as the speed of the fluid increases.

2. What is the minimum speed of airflow required to lift a man?

The minimum speed of airflow required to lift a man depends on various factors such as the weight and body position of the man, the shape and size of the object creating the airflow, and the density of the air. However, on average, a speed of approximately 7-8 meters per second is needed to lift a man.

3. Can a man be lifted by a slow-moving airflow?

Yes, a man can be lifted by a slow-moving airflow, but the amount of lift generated will be significantly less compared to a faster-moving airflow. It is important to note that the speed of airflow is not the only factor that affects lift. Other factors such as the shape and angle of the man's body also play a role.

4. How does the shape of the man affect the speed of airflow needed for lift?

The shape of the man can greatly affect the speed of airflow needed for lift. A more streamlined and aerodynamic shape will require less speed to generate lift compared to a less streamlined shape. This is because a streamlined shape reduces the amount of drag, which can slow down the airflow and decrease lift.

5. Can lift be generated without airflow?

No, lift cannot be generated without airflow. Airflow is necessary for the Bernoulli's principle to come into effect and generate lift. However, there are other methods such as using a propeller or helicopter blades that can create lift without relying on airflow.

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