Evan

As far as more sophisticated configurations go.. without complicating things with Free body diagrams or three dimensional vector solutions... the tension is the same throughout the cable if the system is at rest. If not, there would be motion induced. That is a layman's short cut to the free body diagram of the middle 100 lb wieght supported by the two cables each exerting 50 lbs upward pull. The system is in equilibrium (at rest). For those who are wanting to go further, F=ma=0 at each center of rotation for each pulley and each mass. No acceleration - all forces sum to zero in three dimensions - the system is at rest.

As far as more sophisticated configurations go.. without complicating things with Free body diagrams or three dimensional vector solutions... the tension is the same throughout the cable if the system is at rest. If not, there would be motion induced. That is a layman's short cut to the free body diagram of the middle 100 lb wieght supported by the two cables each exerting 50 lbs upward pull. The system is in equilibrium (at rest). For those who are wanting to go further, F=ma=0 at each center of rotation for each pulley and each mass. No acceleration - all forces sum to zero in three dimensions - the system is at rest.

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