Discover the Force Needed for a Man to Rise on a Bosun Chair | Mass=95Kg

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Homework Help Overview

The discussion revolves around determining the force required for a man to rise while sitting in a bosun chair, with a total mass of 95 kg. The scenario involves a massless rope and a frictionless pulley, prompting participants to analyze the forces at play.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the free body diagram (F.B.D) for the man and the forces acting on him, including tension, weight, and potential acceleration. Questions arise about whether additional F.B.Ds are needed and how forces interact in this setup.

Discussion Status

Some participants have provided calculations related to the forces involved, suggesting that a force of approximately 450 N is needed for equilibrium. Others express uncertainty about the mathematical aspects and the correctness of their diagrams, indicating a mix of interpretations and ongoing exploration of the problem.

Contextual Notes

Participants note the presence of multiple unknowns in the problem, which complicates the analysis. There is also mention of the need for further clarification on the free body diagrams and the overall setup of the forces involved.

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A small man is sitting in a bosun chair that dangles from a massless rope, which runs over a massless frictionless pulley and back down to the mans hand. The combined mass of the man and the chair is 95kg. with what force magnitude must the man pull on the rope if he is to rise?

Mass = 95Kg
a = ?
v = ?
F = ?

I didnt get very far with this one, I drew one F.B.D for the man and got the following:
Nothing in the X direction
y--------T+v = -mg

Heres a link to a drawing
http://img438.imageshack.us/img438/8349/pulley27xt.png

Should i draw another F.B.D for the mans hands on the rope?
 
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if so would T act up onlong with mg and v act downwards?
 
Hi, the weigh of the man + weigh of the chair is around 950 N.
When the man pulls hiomself with his hand with a force F, the chair exerts also a force F on him.
Just to have equilibrium 2F = 950 N so F = 450 N
With a little push up (say with his feet on the ground) the chair and him will move up at a constant speed if he maintains the constant force 450 N on the rope
Any force greather than 450 N will cause an acceleration of the man and the chair up in the air.
I hope it helps you
 
so there's no math involved?
kinda makes sense since there are 3 unknows..

2f = 931N
f = 465.5N

Also there is more to the question..si are my free body diagrams correct?
 
Last edited:

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