How do I find the mass of an object without k?

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To find the mass of an object without knowing the spring constant (k), the discussion revolves around using the period and displacement of a spring system. The user initially struggles with rearranging Hooke's law and the period formula due to missing values for mass and k. They later realize that the spring constant calculated from a known 100g mass (using a displacement of 0.25m and a force of 1N) is 4N/m. The conversation highlights the importance of ensuring that the displacement and period correspond to the same mass for accurate calculations. Ultimately, the user confirms that the spring constant can be applied to other masses in the system.
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Homework Statement
determine the mass of the pink and blue objects by using Hooke's Law and by period.
Relevant Equations
T=2π( √m/k)
F=kx
CaptureD.PNG

time/#periods=T= 30.58/10= 3.058
Displacement=.6m
T=3.058

I tried to rearrange hooke's formula to k=f/x but f=mg and I don't have mass.
Using the period formula is also hard because T=2π( √m/k) and I have neither m or k :/
Please help thanks.
 

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Do you have information about that yellow ##100g## mass?
 
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PeroK said:
Do you have information about that yellow ##100g## mass?
omg wait I didn't think about the 100g thank you. The displacement is 25cm(.25m) and F is 1N so the K=4N/m right? And that's the K I would use for the other masses?
 
swueettea said:
omg wait I didn't think about the 100g thank you. The displacement is 25cm(.25m) and F is 1N so the K=4N/m right? And that's the K I would use for the other masses?
The given displacement and period are not compatible. Is the displacement for the larger mass and the period for the smaller mass?
 
PeroK said:
The given displacement and period are not compatible. Is the displacement for the larger mass and the period for the smaller mass?
The period and the displacement in the post problem is for the pink object but wouldn't the spring constant I found for the 100g object work for all of them? the information I used to find the spring constant I got from the 100g object (the .25m and 1N).
 
swueettea said:
The period and the displacement in the post problem is for the pink object but wouldn't the spring constant I found for the 100g object work for all of them? the information I used to find the spring constant I got from the 100g object (the .25m and 1N).
It's not clear from the diagram what information you have. If you have either the displacement or the period for a known mass, then you can get the spring constant.
 
is this clearer?
Captureg.PNG

But how could I find the spring constant with just the displacement or period if k=f/x and f=mg?
 
PeroK said:
It's not clear from the diagram what information you have. If you have either the displacement or the period for a known mass, then you can get the spring constant.
is this clearer?
View attachment 258807
But how could I find the spring constant with just the displacement or period if k=f/x and f=mg?
 
swueettea said:
is this clearer?
View attachment 258807
But how could I find the spring constant with just the displacement or period if k=f/x and f=mg?
Why can't you get the spring constant from the 100g mass?
 
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PeroK said:
Why can't you get the spring constant from the 100g mass?
Then it'd be 4N/m since 1N/.25m=4N/m right? And I can use that for the pink and blue masses too? Sorry I thought you meant that it was wrong earlier when I had said it so I got really confused.
 
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swueettea said:
Then it'd be 4N/m since 1N/.25m=4N/m right? And I can use that for the pink and blue masses too? Sorry I thought you meant that it was wrong earlier when I had said it so I got really confused.
I assume that's the idea.
 
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  • #12
PeroK said:
I assume that's the idea.
Okay thank you so much for helping me!
 
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