How Does the Radius of a Raindrop Affect Its Acceleration and Terminal Velocity?

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    Falling Physics
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Discussion Overview

The discussion revolves around the effects of the radius of a raindrop on its acceleration and terminal velocity as it falls. Participants explore the relationship between gravitational acceleration, drag forces, and how these factors interact with the raindrop's size and mass.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant suggests that the acceleration of a falling raindrop is equal to gravitational acceleration (g), but expresses uncertainty about the simplicity of this conclusion.
  • Another participant emphasizes the importance of drag force, which is dependent on the surface area of the raindrop, and notes that this drag limits the raindrop's velocity.
  • A third participant recalls a specific result related to the problem, mentioning that the acceleration may be g/7, but does not provide the derivation, suggesting a special substitution for mass is necessary.
  • A later reply agrees with the initial assertion that the only force accelerating the raindrop is gravity, while also noting that terminal velocity is influenced by both mass and radius.
  • There is a suggestion to explore the relationship between gravitational acceleration and terminal velocity, indicating a potential area for further investigation.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between acceleration and terminal velocity, with some agreeing on the role of gravity while others highlight the significance of drag. The discussion remains unresolved regarding the exact relationship and derivation of the acceleration and terminal velocity.

Contextual Notes

Participants do not fully agree on the methods or assumptions needed to analyze the problem, and there are references to specific results without detailed explanations or derivations provided.

hollistb
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So i have a problem with a question in which there is a falling raindrop where the mass and the radius are proportional and i have to find the acceleration with respect to radius and velocity.. I figured that bc it was falling its acceleration would be equal to g... but that seems to easy!
 
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the thing to be considered may be the drag of the drop as it falls down which depends on the surface area of the rain drop. this drag limits the velocity of the drop to a specific number...
 
This is a very old problem. Unfortunately, I remember the answer, g/7, but I don't remember how you get it. It has an unusual solution. There a special substitution that you need to make for the mass, otherwise the problem is insoluble. You might try to research "raindrop problem" with Google.
 
hollistb said:
So i have a problem with a question in which there is a falling raindrop where the mass and the radius are proportional and i have to find the acceleration with respect to radius and velocity.. I figured that bc it was falling its acceleration would be equal to g... but that seems to easy!

Sounds right to me, the only force accelerating a rain drop is due to gravity.

The terminal velocity however depends on the mass and radius.

http://en.wikipedia.org/wiki/Terminal_velocity

Maybe you're supposed to show the relationship between g (the rain drop's acceleration) and the terminal velocity of it.
 

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