Science is the belief in the ignorance of experts. -- Richard Feynman

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Science is the belief in the ignorance of
experts.-- Richard Feynman
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Statics and Dynamics Problem Solving

1. Make a sketch if none given
2. Make FBDs
3. Choose coordinate axes (wisely!)
4. Write for each direction and each
   mass
5. Check that you have enough equations!
6. Solve

Note massless ropes have same tension
everywhere! (Memorize this fact!)
In dynamics problems, you may have to use
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Friction
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What is the tension in rope 1 if the angle ?1
90 (and ?2 is not 90) ?
A 0 B mg/2 C mg D cant tell.
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Is there some angle so that, if you push at a
higher angle (more downward), you can never move
the block, no matter how hard you push?
A yes, if there is friction with the floor B
yes, if there is no friction with the floor C A
B both D no