I and Tim float a long string of closely spaced helium-filled

In summary, the conversation discusses how two people, I and Tim, hang a string of helium-filled balloons over a used-car lot in the shape of a catenary. One person claims that the shape of the string is determined by minimizing the potential energy, while the other person explains that the catenary shape is formed by weight and tension. The balloons, acting as a negative weight, force the same shape as a free-hanging rope. To fully understand the explanation, one would need to look at the differential equations for catenary.
  • #1
Pranav Jha
141
1
I and Tim float a long string of closely spaced helium-filled balloons over his used-car lot. We
secure both ends of the string to the ground several meters apart so that the balloons float over the lot in forming the shape of a catenary. Why that shape?
 
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  • #2


My claim is that the shape of the string is such that the potential energy of the sting is minimized.
 
  • #3


Feldoh said:
My claim is that the shape of the string is such that the potential energy of the sting is minimized.

Please explain that statement
 
  • #4


Catenary is formed under two forces - weight and tension. Here, you made the weight negative, by attaching balloons.

Now, if you want to know why catenary is the curve made by free-hanging rope, you need to look at the differential equations for it. But it should be clear why balloons force the same shape, only upside down.
 
  • #5


K^2 said:
Catenary is formed under two forces - weight and tension. Here, you made the weight negative, by attaching balloons.

Now, if you want to know why catenary is the curve made by free-hanging rope, you need to look at the differential equations for it. But it should be clear why balloons force the same shape, only upside down.

sorry but i am still clueless about how to understand your explanation
 

1. How does the helium-filled string float?

The helium-filled string floats due to the buoyancy force, which is caused by the difference in density between helium and air. Helium is less dense than air, so it rises and creates an upward force on the string, allowing it to float.

2. What makes the helium-filled string stay in a straight line?

The helium-filled string stays in a straight line due to the evenly spaced helium pockets along its length. Each pocket of helium provides an equal upward force, resulting in a balanced tension along the string that keeps it straight.

3. How closely spaced are the helium-filled pockets on the string?

The helium-filled pockets on the string are typically spaced very tightly, usually only a few centimeters apart. This close spacing ensures that the buoyancy force is evenly distributed along the entire length of the string.

4. Can the helium-filled string support any weight?

The amount of weight that the helium-filled string can support depends on the length and thickness of the string, as well as the amount of helium and the strength of the material. In general, longer and thicker strings with more helium will be able to support more weight.

5. How does the helium-filled string behave in different environments?

The behavior of the helium-filled string may vary in different environments, as factors such as temperature, air pressure, and wind can affect the buoyancy force and the overall stability of the string. It is important to carefully consider these factors when using the string in different settings.

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