How do masses and pulleys behave in a balanced system with different weights?

  • Thread starter Thread starter Amir80om
  • Start date Start date
  • Tags Tags
    Pulleys Series
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
10 replies · 2K views
Amir80om
Messages
1
Reaction score
0

Homework Statement


Sorry for bad english[/B]
There is serie of mass and pulleys. We Know we have more than two masses. System is balanced.We take m(m<<1) from on of the masses and add to another one.
a) prove all the masses except these two have downward acceleration
b) prove mass with heavier has acceleration downward and mass with lighter has acceleration upward
c) prove that all acclerations are relevant to m^2

Homework Equations

The Attempt at a Solution


a) First System is balanced and when we take m out of one mass there will be acceleration => speed of center of mass will increase => potential energy of center of mass will reduce => center of mass has downward acceleration => T is Force that connects pulleys to wall and M is sum of all masses T<MG I don't Know how to prove this for all the masses individually.
b) since all the mass except two masses have downward acclerations and length of rope is constant one of two masses or both of them must have acclerations upward. Heavier mass is going down relevant to lighter mass but I don't know how to prove (b)
 
Last edited:
Physics news on Phys.org
Amir80om said:

Homework Statement


Sorry for bad english[/B]
There is serie of mass and pulleys. We Know we have more than two masses. System is balanced.We take m(m<<1) from on of the masses and add to another one.
a) prove all the masses except these two have downward acceleration
b) prove mass with heavier has acceleration downward and mass with lighter has acceleration upward
c) prove that all acclerations are relevant to m^2

Homework Equations

The Attempt at a Solution


a) First System is balanced and when we take m out of one mass there will be acceleration => speed of center of mass will increase => potential energy of center of mass will reduce => center of mass has downward acceleration => T is Force that connects pulleys to wall and M is sum of all masses T<MG I don't Know how to prove this for all the masses individually.
b) since all the mass except two masses have downward acclerations and length of rope is constant one of two masses or both of them must have acclerations upward. Heavier mass is going down relevant to lighter mass but I don't know how to prove (b)
Is there a diagram of this thing, or are we supposed to have ESP?
 
It would be useful if you could upload a diagram or a sketch of the system, as it is difficult to visualize the masses that should be hanging.

PD: If your native language is Spanish or French I could post the answer with it.
 
Chestermiller said:
Is there a diagram of this thing, or are we supposed to have ESP?
My impression is that there is no specific set-up. One is supposed to demonstrate these as general results.
I think I see how to do it if we can assume that it is a single string running through the system.
 
haruspex said:
Please do not. This is a homework forum. Read the guidelines.

I mean I could offer the tips and/or explanations required in the native language of the OP so it's easier for them to read. I don't see how that is against the guidelines.
 
CharlieCW said:
I mean I could offer the tips and/or explanations required in the native language of the OP so it's easier for them to read. I don't see how that is against the guidelines.
But your words were "post the answer".
 
Last edited:
CharlieCW said:
I mean I could offer the tips and/or explanations required in the native language of the OP so it's easier for them to read. I don't see how that is against the guidelines.
I interpreted your use of "answer" to mean "reply".
The forum rules state that the language used for posting must be English.
 
  • Like
Likes   Reactions: CharlieCW and Chestermiller
haruspex said:
But that would be "an answer", not "the answer".
And that I'd put down to language/translation issues :smile:
I try to be a little flexible when it appears that the poster's first language is not English.