Vertical spring connected between two bodies with a rope above them

[physics1000]

Homework Statement

Yes, homework

Relevant Equations

There is no equation in here

Question:
A string spring is connected between two bodys with a rope above them.
M1 = 25Kg
M2 = 50KG
Distance between them is 100m.
I answered a bit and got to the point where the distance between the two masses are 110m ( the mass below got 10m lower and is on balance, I mean, acceleration = 0.
Anyway, in that point, The question is:
The rope has been cut, what is the acceleration?

I couldn't really understand what I should say...
I thought of that:
M1 ( the above mass ) has m1g + Fk below
M2 ( the below mass ) has only m2g.

Am I right in doing this? the reason Fk is not in M2 because the string doesn't do a thing to him, but to M1 it does, because it is heavier.
Am I right?

[Mentor Note -- some corrections applied to this post]

 

[hmmm27]

Is the rest of the problem on a different forum ?

 

[physics1000]

Is the rest of the problem on a different forum ?

Nope, its the last sub-question on the question. ( There is A,B,C):
A - is something else, not related.
B- Is what I said regarding the distance from 100 to 110.
C - is the cut rope

 

[hmmm27]

read.

 

[physics1000]

read.

I did read it before.
What is the problem exactly? I don't have a painting? well,, you can understand its a little problematic to paint here right? I can paint:

This is how the question looks like.
Just what it means when i cut the rope.. that's my sole question.
If what i said above is true?

thats the question

 

[berkeman]

Welcome to PF.

Your thread title says "string", but your figure seems to imply "spring". I can fix your thread title for you if you meant "spring".

Also, what is the rope? Is it holding the masses at some separation before it is cut?

 

[physics1000]

Welcome to PF.

Your thread title says "string", but your figure seems to imply "spring". I can fix your thread title for you if you meant "spring".

Also, what is the rope? Is it holding the masses at some separation before it is cut?

Oh opps, my bad.
Sorry, meant spring, I don't know why I wrote string... sorry, my bad.
Regarding the rope:
It is holding the masses.
According to my question:
M1 is 25KG.
M2 is 50KG
I had to find the point where M2 is in balance, It means Acceleration=0. I found it, it is 10 meter below the starting point.
Then for the question of this thread:
What happens if, from that point of the 10meter below the starting point, the rope is being cut?
What I thought is:
M2 has force of m2G below only.
M1 has force of m1G and Fk below.

Reasons for my thoughts:
M2 is heavier then m1, thus, the spring is not doing a thing to him.
in the other hand, M1 is lighter, thus, he will be carried more faster to M2, that's why he has Fk below, means, M1G+Fk is the force below.

Is it true?
Or my other thought ( but less logical ):
M2 has M2G below and FK above, of 10meter ( I thought maybe it returns to his base- starting point ).
M1 has M2G below and Fk below also ( goes 10m down ).

But this thought is less logical then the first, the first one sounds more true to me, but I want to be sure.

 

[haruspex]

M2 is heavier then m1, thus, the spring is not doing a thing to him.

If the spring has no mass then there cannot be a net force on it. What does that tell you about the forces the spring exerts on the two masses?

What happens if, from that point of the 10meter below the starting point, the rope is being cut?

That's a bit vague. Do you just want the instantaneous acceleration of each mass, or of just one mass, or how the whole system moves thereafter?

M2 has M2G below and FK above

And what is the value of Fk at the instant the rope is cut?

M1 has M2G below and Fk below

M1 doesn’t 'know' anything about M2. All it experiences are its own weight, the force from the spring, and, until it is cut, the force from the rope.

 

[physics1000]

If the spring has no mass then there cannot be a net force on it. What does that tell you about the forces the spring exerts on the two masses?

That's a bit vague. Do you just want the instantaneous acceleration of each mass, or of just one mass, or how the whole system moves thereafter?

And what is the value of Fk at the instant the rope is cut?

M1 doesn’t 'know' anything about M2. All it experiences are its own weight, the force from the spring, and, until it is cut, the force from the rope.

Ahh, I see.
I will try to make a solution
Is it Possible I will write in my notebook and send a picture here? because I don't know how to write it all ( plus paintings ) in forum.

 

[haruspex]

Ahh, I see.
I will try to make a solution
Is it Possible I will write in my notebook and send a picture here? because I don't know how to write it all ( plus paintings ) in forum.

Images are for diagrams and textbook extracts. Please take the trouble to type in your working.
Latex is preferred (click LaTeX Guide below the text entry panel), but not essential.

 

[physics1000]

Images are for diagrams and textbook extracts. Please take the trouble to type in your working.
Latex is preferred (click LaTeX Guide below the text entry panel), but not essential.

Problem is, there isn't any much writing in this question, its mostly the painting itself.
But okay, I will try, I will send a picture of the painting and write what I did here.

 

[physics1000]

EDIT:
Here was a picture of my last solution before the actual one.
It was wrong, don't mind it.

 

[physics1000]

You can close post, I got good with this question...
Thanks anyway ( although I didnt get any answers ).

 

[haruspex]

You can close post, I got good with this question...
Thanks anyway ( although I didnt get any answers ).

What answer did you get? It bothers me that your diagram still does not show a force exerted on M1 by the spring.

 

[physics1000]

What answer did you get? It bothers me that your diagram still does not show a force exerted on M1 by the spring.

Oh the one in the picture is wrong.
I thought it is meaningless to post an answer, since no one tried to answer :/
but anyway, I got it solved, thanks anyway :)

 

[haruspex]

Oh the one in the picture is wrong.
I thought it is meaningless to post an answer, since no one tried to answer :/
but anyway, I got it solved, thanks anyway :)

It's not that nobody tried. I had to go out for a while. Using a forum provided by volunteers you need to be patient.
Do you know that your answer is correct? If not, please post it.

 

[physics1000]

It's not that nobody tried. I had to go out for a while. Using a forum provided by volunteers you need to be patient.
Do you know that your answer is correct? If not, please post it.

I didnt blame you or something, you don't have any commitment to answer to me ( sorry if you felt so because of what I wrote ). I wasnt mad or anything about it ( now I understand what I wrote looks like, sorry about it ), just thought it was matterless.
Problem is, now to write all I wrote in latex here.. its hell lol. ( I will edit the comment with the picture, say it is wrong and delete picture ).
Thanks anyway :)