Capillary Tube Behavior in a Gravityless Environment

AI Thread Summary
In a gravityless environment, such as a freely falling elevator, the behavior of a capillary tube filled with water changes significantly. Initially, the water rises to 8 cm due to adhesive forces, but once in free fall, these forces can dominate without the counteracting force of gravity. As a result, the water will rise to fill the entire 20 cm length of the capillary tube. The discussion highlights the importance of understanding the forces acting on the fluid in different conditions. Thus, the correct answer to the problem is that the water column will occupy the full length of the capillary tube at 20 cm.
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Homework Statement


A 20 cm long capillary tube is dipled in water.The water rises up to 8cm .if the entire arrangement is put in a freely falling elevator ,the length of the water column is

A)10cm

B)8cm

C)20cm

D)4cm

Homework Equations


Its a theoretical sum

The Attempt at a Solution


Okay...since this is a freely falling elevator ,the reletive accelaration will be zero and hence i feel the fluid will maintain its orignal height of 8cm

But alas ,the book says its 20cm and have give the reason that since its "gravityless" ie :rel accelaration 0, it will occupy full capillary tube.

[Edit 1 -fixed a typo
Edit 2 - i wrote about what i did in Edit 1]
 
Last edited:
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What are the forces acting on the column of water in the capillary before you put it in the elevator? What force is pulling the water up the capillary against gravity?
 
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Chandra Prayaga said:
What are the forces acting on the column of water in the capillary before you put it in the elevator? What force is pulling the water up the capillary against gravity?

Oh ! I think i got it !
Case 1
Alright ,so before we put the fluid in the elevator we have forces of adhesion pulling water up the capillary tube,but one it reaches a certain hieght ,force of gravity dominates and hence it can't go further

Case 2
During free fall there is nothing to stop the liquid from rising ,that is ,due to adhesion the liquid continues to rise until it occupies full cappilary tube !
 
Hence the answer should be 20 cm right ?
 

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