How can I calculate the compression of a support column under a heavier weight?

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To calculate the compression of a support column under a heavier weight, the equation F=KX is used, where F is the force, K is the stiffness, and X is the compression. Given a weight of 5.42 x 10^5 N causing a compression of 2.46 x 10^-4 m, the stiffness K is calculated to be approximately 2.2 billion N/m. Using this K value, the compression under a new weight of 4.8 x 10^6 N is found to be 0.0022 m, confirming the calculations are correct. An alternative method using a ratio also yields the same result, demonstrating the consistency of the solution. The discussion emphasizes the importance of understanding elastic behavior in accordance with Hooke's law.
kkmonte
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Homework Statement



A support column is compressed 2.46 x 10^ -4m under a weight of 5.42 X 10^5N. how much is the column compressed under a weight of 4.8 X10^6N?

Homework Equations



F=KX

The Attempt at a Solution



By using that equation, I get 542000 = .000246K



Solve for K, and I get a huge number, 2,203,252,032.52



Then by using that number as my new K, and solving for the compressed distance with the new weight, I get 0.0022 m.



Is that the right answer?



Similarly, I figured I could just make a ratio proportion of:



.000246....X

------------- = ----------------

542,000....4,800,000



Which also gives me an answer of 0.0022 m (2.2 X 10^ -3). Is this correct?
 
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Yes, either method gives you the correct solution, as long as the column is still behaving elastically in accordance with Hooke's law.
 
Thanks Jay, when I first did this problem, I was looking at the answer of 2.2e-3 and shaking my head going how can this thing compress less when there is a heavier weight on it? However it wasn't after I was typing it in the computer that I realized that the first compression is 2.46e-4, and I went, duh. =)

Thanks for letting me know I'm correct.
Ken
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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