Archimedes principle free fall problem

AI Thread Summary
Archimedes' principle does not hold in a vessel in free fall, as the lack of gravitational forces alters the behavior of fluids, making buoyancy ineffective. In a free-fall scenario, fluids lose their cohesion, resembling a state similar to a pool of mercury. Regarding the second question, the difficulty of submerging two identical hollow bodies, one with a hole, depends on the definition of "difficult." The body with the hole may experience less buoyancy due to water entering, potentially making it easier to submerge, but this is contingent on the interpretation of difficulty. Overall, buoyancy relies on gravity, which is absent in free-fall conditions.
heidari
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I have 2 question about the Archimedes principle?
1. does it hold in a vessel in a free fall? why?
2. if we imppressed 2 same hollow bodies in water, and just one of them has a hole at the bottom. which one is more difficult and why?

thank you!
 
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I assume you're talkng about buoyancy. Re question 1) I would say no, first off a fluid becomes a somewhat different creature in free fall. without external confinement, the forces keeping it in one place are unlikely to provide enough cohesion--I would think of it sort of like a pool of mercury. Without weight of either fluid or object, it sort of lacks meaning.

for 2) what do you think? Imagine a golf ball sized whiffle ball vs a pingpong ball. Remember archimedes said buoyancy forces are proportional to the volume displaced.
 
Buoyancy depends on gravity so it won't operate in free-fall. If you had a globule of water in zero-G and gently placed something inside it, the object would stay still except for currents. You can't have 'floating' if there's no up or down.

2. if we imppressed 2 same hollow bodies in water, and just one of them has a hole at the bottom. which one is more difficult and why?

I don't know what you mean by 'difficult'.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...

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