Saitama
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Chestermiller said:
About your Method 1, Can we narrow down our region? What is the significance of having no vertical forces along the dotted lines?
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About your Method 1, Can we narrow down our region? What is the significance of having no vertical forces along the dotted lines?
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Pranav-Arora said:About your Method 1, Can we narrow down our region? What is the significance of having no vertical forces along the dotted lines?
I used as a free body the region of film and string between the dotted lines. There are only two vertical forces acting on this free body, the force F downward, and the force of the frame at the top (pointing upward). The force of the frame between the dotted lines (pointing upward), by Newton's third law, is the same as the force of surface tension between the dotted lines acting downward on the frame.