Pulley system problem: 6 Pulleys and 1 Mass

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SUMMARY

The discussion centers on a pulley system analysis involving a block of mass m1 = 5kg and a force F applied to the string. The calculations confirm that the tension in the strings, T1 and T2, equals 50N, derived from the equation T1 = gm1. The free body diagrams for the mass and pulleys are correctly reasoned, leading to the conclusion that T1 equals T2, validating the applied force as 50N. The participant seeks confirmation of their reasoning, which is affirmed by others in the discussion.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Basic knowledge of free body diagrams
  • Familiarity with tension in strings and pulleys
  • Concept of gravitational force (g = 10 m/s²)
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  • Explore Khan Academy resources on mechanics
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david3305
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Homework Statement
Find force F
Relevant Equations
m_1 = 5kg, g = 10 m/s^2
The following system is at rest with a block of mass m1 = 5kg, and a force F that is applied to the end of a string attached to the pulley system. Let g, the acceleration due to gravity equal to 10 (for simple calculations).

pulley1.jpg

My analysis is as follows:

I'll first label the strings Tsub1 and Tsub2, and each pulley in red P1 and P2 (in red):

pulley2.jpg


From here I'll make 3 free body diagrams:

m1:
pulley3.jpg

$$\begin{array}{rcl} & T_{1} = gm_{1} = 50N \\ \end{array}$$

then P1:
pulley5.jpg


$$\begin{array}{rcl} &T_{x} = 2T_{1} \end{array}$$

then P2:

pulley6.jpg


$$\begin{array}{rcl} &T_{x} = 2T_{2} \end{array}$$

From these equations we have that

$$\begin{array}{rcl} &T_{1} = T_{2} \end{array}$$

and therefore

$$\begin{array}{rcl} &T_{1} = T_{2} = F = 50N \end{array}$$
 
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Is there a question you wish to ask about this?
 
Sorry, I just wanted to know if my reasoning is correct. Im just a simple man trying to figure out stuff on my own without any formal training. In fact, I didn't even took physics in highschool, back in the day it wasn't required on my 3rd world country.
 
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david3305 said:
Sorry, I just wanted to know if my reasoning is correct. Im just a simple man trying to figure out stuff on my own without any formal training. In fact, I didn't even took physics in highschool, back in the day it wasn't required on my 3rd world country.
If you do/don't have formal training, your free body diagrams look well done/reasoned to me.
 
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erobz said:
If you do/don't have formal training, your free body diagrams look well done/reasoned to me.
Thanks, thats Khan Academy and a bunch of youtube videos for you.
 
david3305 said:
Sorry, I just wanted to know if my reasoning is correct. Im just a simple man trying to figure out stuff on my own without any formal training. In fact, I didn't even took physics in highschool, back in the day it wasn't required on my 3rd world country.
Your reasoning is correct. I wish that more of my students explained theirs as clearly as you did.
 
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