Looking for an equation related to lifting force of air

  • Thread starter Thread starter Paranemertes
  • Start date Start date
  • Tags Tags
    Air Force Lifting
AI Thread Summary
Hot air balloonists determine the necessary balloon size for lifting by using the principles of buoyancy and weight. The key equation involves balancing the total weight of the basket, balloon, and air against the buoyant force generated by the volume of air displaced. The buoyant force is calculated using the density of the surrounding air and gravitational acceleration. A helpful resource was shared, detailing the physics of ballooning, which can assist in understanding these concepts further. Understanding these forces is crucial for effective hot air balloon design and operation.
Paranemertes
Messages
3
Reaction score
0
Hello,

I've been wondering for a while now how hot air balloonists figured out how big their balloons needed to be to lift themselves, the basket,the balloon itself, ect. Is there an equation that would tell me how much lifting force I could get out of x amount of air at x temperature, what volume that would take up, and maybe the pressure?

Thanks!
 
Last edited:
Physics news on Phys.org
I didn't read the document, but you can construct a basic model just by knowing two forces: the bouyancy force and the weight force.

(mass_basket+mass_balloon+mass_air_in_balloon)*g = Volume_balloon*g*density_surrounding_air

This equation would be for if the balloon were not accelerating up or down.
 
Yep, that is very similar to what this fine gentleman derived. Thanks!
 

Thread '1:1 versus 2:1 Mechanical Advantage debate'

The rope is tied into the person (the load of 200 pounds) and the rope goes up from the person to a fixed pulley and back down to his hands. He hauls the rope to suspend himself in the air. What is the mechanical advantage of the system? The person will indeed only have to lift half of his body weight (roughly 100 pounds) because he now lessened the load by that same amount. This APPEARS to be a 2:1 because he can hold himself with half the force, but my question is: is that mechanical...
View full post »

Thread 'Newton's first law?'

Some physics textbook writer told me that Newton's first law applies only on bodies that feel no interactions at all. He said that if a body is on rest or moves in constant velocity, there is no external force acting on it. But I have heard another form of the law that says the net force acting on a body must be zero. This means there is interactions involved after all. So which one is correct?
View full post »
Thread 'Beam on an inclined plane'

Thread 'Beam on an inclined plane'

Hello! I have a question regarding a beam on an inclined plane. I was considering a beam resting on two supports attached to an inclined plane. I was almost sure that the lower support must be more loaded. My imagination about this problem is shown in the picture below. Here is how I wrote the condition of equilibrium forces: $$ \begin{cases} F_{g\parallel}=F_{t1}+F_{t2}, \\ F_{g\perp}=F_{r1}+F_{r2} \end{cases}. $$ On the other hand...
View full post »

Similar threads

I Lift Force of a Rotating Sphere in the Air
Replies
7
Views
3K
Rocket propulsion explained only through pressure differential
Replies
46
Views
4K
Flow of air through an open tube with a balloon
Replies
9
Views
3K
Keeping helium in an unsealed balloon?
Replies
8
Views
2K
Uses of Lift Force for Plane Surfaces
Replies
23
Views
3K
B What forces are required to tumble a block?
Replies
16
Views
2K
I Drag equation - relative flow velocity
Replies
11
Views
3K
Optimal Size of Rocket Engine Nozzle for Vacuum Performance
Replies
26
Views
3K
Clarifying the Definition Total/Stagnation Pressure (p₀) in Bernoulli'
Replies
2
Views
878
Lift: Probably my last question
Replies
7
Views
2K

Hot Threads

Recent Insights

Back
Top