Tension and Pulleys Cannot understand this problem

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The discussion centers on a physics problem involving tension and pulleys, specifically how to calculate the force needed for a man in a bosun's chair to rise at constant velocity. The confusion arises around the equation 2T = mg + ma, where T represents tension, m is the combined mass of the man and chair, and a is acceleration. Participants suggest drawing a free body diagram to clarify the number of tension forces and their directions, emphasizing that tensions cannot simply cancel each other out in this scenario. The conversation highlights the importance of understanding the dynamics of forces in pulley systems. Overall, grasping these concepts is essential for solving similar problems effectively.
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Tension and Pulleys...Cannot understand this problem

So this is NOT for homework, (I'm doing practice problems reviewing for a final), but this is a textbook question that might as well be homework.

This is the question:

Figure 5-53 shows a man sitting in a bosun’s chair that dangles from a massless rope, which runs over a massless, frictionless pulley and back down to the man’s hand. The combined mass of man and chair is 95.0 kg. With what force magnitude must the man pull on the rope if he is to rise (a) with a constant velocity?


After looking at the solution, the part that confuses me is the 2T. I don't understand why 2T=mg+ma (m is the mass of the man-pulley) is the equation that we can use. Doesn't the tension cancel out so that mg=F, where F is the force of the hand pulling?

Thank you for taking the time to read this.
 
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goddard said:
After looking at the solution, the part that confuses me is the 2T. I don't understand why 2T=mg+ma

Draw a free body diagram. How many tension forces T are there?

goddard said:
Doesn't the tension cancel out so that mg=F, where F is the force of the hand pulling?

What direction are these tensions in? Is it possible for them to "cancel" each other out?
 
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