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additional relations

Now we need to figure out what are the relations between tex2html_wrap_inline838 , tex2html_wrap_inline840 , and tex2html_wrap_inline742 . tex2html_wrap_inline838 and tex2html_wrap_inline840 have to have the same magnitude. This was discussed earlier when we considered examples with forces. If tex2html_wrap_inline848 moves up one ince, tex2html_wrap_inline850 must move down the same distance. But their directions are opposite. Therefore


If tex2html_wrap_inline840 is positive then the pulley spins around in the counterclockwise direction. By the right hand rule, if you curl you right hand around the pulley in the direction of motion, then your thumb sticks out of the page, which is the positive tex2html_wrap_inline822 direction. Therefore




Joshua Deutsch
Sun Feb 23 15:54:50 PST 1997