Can You Simplify Calculating Drag Coefficient for an Inverted Cone?

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Homework Help Overview

The discussion revolves around calculating the air drag coefficient for an inverted cone dropped from a height. The original poster describes their experimental setup and seeks a simpler method for deriving the drag coefficient, which involves complex equations of motion.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants explore the material properties of the cone and its impact on drag measurement, questioning whether the cone is solid or made of paper. There are suggestions for ensuring the cone reaches terminal velocity and methods for measuring velocity accurately.

Discussion Status

The discussion is active, with participants providing insights on the conditions necessary for accurate measurements and the implications of the cone's material. Some guidance has been offered regarding the setup and measurement techniques, but no consensus has been reached on a definitive method.

Contextual Notes

Participants are considering various factors such as the cone's weight, shape, and stability, which may affect the drag coefficient calculation. There is also a focus on ensuring that the cone reaches terminal velocity during the drop.

fizzyfiz
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Summary: Hello, I have a task to calculate the air drag coeficient experimentally. I have a cone which I had dropped from height of 1.5 m and measured the time. Then I derived the equation of of velocity and acceleration but they are very complicated. Is there any simpler method?

a=g-k/m*V^2
 
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Is the cone solid, made of lead ? Please be a little complete ...
 
A cone made from a rolled up and taped piece of paper could reach its terminal velocity in 1.5 m, so you should be able to get a good measurement of drag coefficient. On the other hand, a cone made of wood or metal would be almost unaffected by air drag in that distance, so it would be almost impossible to measure drag coefficient.

A simple method would be to drop the cone from a height high enough that it reaches terminal velocity. Then measure the size, weight, and velocity, and calculate the drag coefficient directly from the drag equation. Velocity can be measured using a video camera with a ruler in the background.
 
Ok so I should mark heights and I will know that cone reached its terminal velocity if the same distance will be traveled in equal times?
 
Hollow paper it is. Tape light enough ? Ratio height/diameter ? Tip up or down ? Stabilized ?
As
BvU said:
Please be a little complete ...

fizzyfiz said:
reached its terminal velocity if the same distance will be traveled in equal times?

Yep. Maybe use a video.
 
It is a cone made of paper, tip down, 80g/m^2 . I caculated mass
 
BvU said:
Hollow paper it is. Tape light enough ? Ratio height/diameter ? Tip up or down ? Stabilized ?
Hollow paper
1571903904825.png
, tip down
1571903907108.png
. One by one they come out. I keep on dragging for the others ...

Can you calculate a terminal velocity for an inverted cone ?
 

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