A different type of pulley question -help

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SUMMARY

The discussion centers on calculating the force required for a person in a box to pull themselves up using an ideal pulley system. When the individual pulls down on one end of the rope, the ideal pulley configuration results in a double upward force acting on the person and the box combined. To find the force needed for constant velocity, one must apply Newton's 2nd law, considering all forces acting on the system. The conversation also touches on the scenario of upward acceleration, emphasizing the importance of understanding the forces involved.

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murphy
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Okay, I have this crazy pulley question where a guy is sitting in a box that is attached to a pulley on the ceiling (the pulley system is ideal). He pulls himself up at a constant velocity -how do i find the force needed for him to pull himself up? (the rope goes around the pulley and back down to him- halfway around the pulley)
What about if he is accelerating upwards?
 
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Identify all the forces acting on the "man + box" (treat them as a unit). Note that the man pulls down on one end of the rope, but both ends of the rope pull up on him. Apply Newton's 2nd law.

You may find this discussion helpful: https://www.physicsforums.com/showthread.php?t=46892
 
thanks! I got it! - I didn't realize that the man had double force pulling up on him!
 

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