IACalculate Maximum Compression Distance of a Spring with Vertical Placement

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The discussion focuses on calculating the maximum compression distance of a spring when a 1.70 kg book is dropped from a height of 0.70 m onto it. The user applies the conservation of energy principle, equating potential energy and spring energy, leading to the equation mg(y+x) = 1/2kx^2. After adjusting the equations, they derive a quadratic equation and calculate the compression distance to be 0.142 meters. A participant points out that the spring constant was initially missing, but confirms the user's reasoning is correct once the value of 1400 N/m is provided. The conversation emphasizes the importance of including all necessary variables in physics calculations.
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I just need to make sure I understand how to do this and that I am doing everything correctly. Could someone check my work please?


You place the spring vertically with one end on the floor. You then drop a 1.70 kg book onto it from a height of 0.70 m above the top of the spring. Find the maximum distance the spring will be compressed.
So
k_1 + U_1 + W_{other} = k_2 + U_2
I have that

k_1=0, U_1= mgy_1, W_o=0, k_2=0, U_2=1/2kx^2

So the issue is that I have to the potential energy to the start of the spring plus the distance the spring compresses.

To solve this I need to adjust the equations to look like

mg(y+x)=1/2kx^2

This works out to a homogenous quadradic that looks like

1/2kx^2-mgx-mgy=0

Plugining in values and solving gets me

0.142 meters.

TIA

T
 
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You didn't include the spring constant, so I can't check your arithmetic, but your reasoning looks faultless to me. Good job. :)
 
Diane_ said:
You didn't include the spring constant, so I can't check your arithmetic, but your reasoning looks faultless to me. Good job. :)

oops...sorry about that.

It should be 1400N/m...and thanks :smile:
 
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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