Determine the tension in each section of rope

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Homework Help Overview

The discussion revolves around a physics problem involving a pulley system used to lift a piano, focusing on the calculation of tension in various sections of rope. The original poster seeks assistance specifically with determining the tension in FT3.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the forces acting on the pulley system and the equilibrium conditions necessary for lifting the piano. There are attempts to derive the tension in FT3 based on the tensions in FT1, FT2, and FT4. Some participants question the assumptions made regarding the forces acting on the pulley.

Discussion Status

The discussion has progressed with participants sharing their thoughts on the tension values and engaging in reasoning about the forces involved. One participant expresses uncertainty about their previous conclusions regarding FT3, while another suggests drawing a free body diagram to clarify the forces at play. The original poster indicates they have reached a resolution with the help of the discussion.

Contextual Notes

Participants are working under the constraints of a homework assignment, which may limit the information they can use or the methods they can apply. The original poster has provided their initial answers for the tensions in FT1, FT2, and FT4, but is specifically seeking help for FT3.

helppleaseee
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1.
picture of problem:
http://img.photobucket.com/albums/v223/lilaznbabe/4_56.gif

(a) What minimum force F is needed to lift the piano (mass M) using the pulley apparatus shown in Fig. 4-56? (Enter your answers in terms of some multiple of Mg.)
____ Mg (I got .5)
(b) Determine the tension in each section of rope: FT1, FT2, FT3, and FT4.
Tension in FT1?
____ Mg (I got .5)
Tension in FT2?
____ Mg (I got .5)
Tension in FT3?
____ Mg
Tension in FT4?
____ Mg (I got 1)

ok so i only need help on FT3...
thanks!
 
Last edited by a moderator:
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helppleaseee said:
1.
picture of problem:
http://img.photobucket.com/albums/v223/lilaznbabe/4_56.gif

(a) What minimum force F is needed to lift the piano (mass M) using the pulley apparatus shown in Fig. 4-56? (Enter your answers in terms of some multiple of Mg.)
____ Mg (I got .5)
(b) Determine the tension in each section of rope: FT1, FT2, FT3, and FT4.
Tension in FT1?
____ Mg (I got .5)
Tension in FT2?
____ Mg (I got .5)
Tension in FT3?
____ Mg
Tension in FT4?
____ Mg (I got 1)

ok so i only need help on FT3...
thanks!
the best you can do is approximate it by assuming all tension forces on the upper pulley act vertically. You've got the others correct, so why not continue in the same manner to solve for FT3 in the same manner using Newton 1?
 
Last edited by a moderator:
i initially thought it was 1...but that is wrong, then i thought .5 but something tells me that's not right. :frown:
 
what is causing the tension in #3?

draw a FBD of the pulley with all the forces on it

in order for this system to be in equilibrium the sum of the forces must be 0,

so the forces up must equal the forces down
 
yay! thanks soooo much i got it!
 

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