In Which I Fail Physics 101…

… but pass it on a retake!

While quickly building an ad hoc washing line pulley assembly from a bag of hooks, eyes, and pulleys, and a 2×4, I put this together at first (blotted out some background for privacy of myself and neighbours – click for larger view):

bad design

Huh. Does not want to hang level. Why? A tenth of a second after the thought, I burst out laughing loudly at my error. Ironic since I love teaching about pulleys in basic physics, and for some reason students are scared of pulleys. (Not as scared as they are of torque (why?), but scared nonetheless. I try to help them overcome those fears.) I made an obvious mistake. (Do you see it?)
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