Relationship of acceleration in two-pulley system

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Homework Help Overview

The discussion revolves around the relationship between the accelerations of two masses in a two-pulley system. Participants are exploring how the movements of the masses relate to each other, particularly focusing on the accelerations a1 and a2.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants are attempting to understand the relationship between the distances moved by the two masses and how that affects their accelerations. There are questions about whether the acceleration of m1 is double that of m2 or vice versa, with some participants suggesting different relationships based on their interpretations of the pulley system.

Discussion Status

There is ongoing confusion regarding the correct relationship between a1 and a2, with multiple interpretations being explored. Some participants have proposed that a2 = 2a1, while others suggest a1 = 2a2. Guidance has been offered to reconsider the relationships between the distances moved by the masses, but no consensus has been reached.

Contextual Notes

Participants are working under the constraints of a homework assignment, which may limit the information they can use. There are also discussions about the relevance of certain equations and assumptions regarding the lengths of the segments in the pulley system.

jake jungle
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Homework Statement


upload_2015-2-4_20-24-52.png

What is the relationship between a1 and a2
A.a1=a2
B.a1=2a2
C.a2=2a1
D.a1=a2√2
E.a2=a1√2
F.There is no simple relationship between the two acceleration

Homework Equations


a = F/m

The Attempt at a Solution


I am quite confused with the second pulley , so the weight of m2 is divided to 2 tension through the second pulley , but i can't find what is the magnitude of the upper tension ,therefore we can't find the lower tension or the acceleration either.
So i choose F as my answer , however i am not sure . Is my answer right ?.
 
Last edited:
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Conserve string.
 
DEvens said:
Conserve string.

sorry i don't get it . can you be more specific , and which answer do you choose :D
 
Really? That's not enough?

Ok. When mass m1 moves a distance of 1 unit, how far must the mass m2 move?
 
That's where i was confused.
If m2 goes a distance of x. Will m1 goes a distance of x/2 or 2x?
 
jake jungle said:
That's where i was confused.
If m2 goes a distance of x. Will m1 goes a distance of x/2 or 2x?
Let the lengths of the horizontal portions be x (on the left), y (top right), z (lower right).
What equations relate them?
 
I have the same problem too
haruspex said:
Let the lengths of the horizontal portions be x (on the left), y (top right), z (lower right).
What equations relate them?

I think that it is Δx = Δy + Δz
Since Δy is the same as Δz, so Δx = 2Δy = 2Δz
So, a2 = 2a1, right ?
 
Try again.
 
BvU said:
Try again.
Hmm..
I tried and got the same answer, a2 = 2a1
Please explain the correct answer to me

EDIT :
Tried again and get a1 = 2a2
 
Last edited:
  • #10
terryds said:
Tried again and get a1 = 2a2
Good.
 
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  • #11
terryds said:
Hmm..
I tried and got the same answer, a2 = 2a1
Please explain the correct answer to me

EDIT :
Tried again and get a1 = 2a2

sr i didnt understand , since S = 1/2 at^2
then if Δx=2Δy .
then ax should be equal 2 ay ?
then a2 = 2a1 ?
 
  • #12
jake jungle said:
sr i didnt understand , since S = 1/2 at^2
That's irrelevant to how the lengths x, y and z relate.
jake jungle said:
then if Δx=2Δy .
It isn't.
What combinations of lengths x, y and z are known to be constant?
 

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