224_Physics ProblemsTechnical Physics

# 224_Physics ProblemsTechnical Physics - 226 *P8.20...

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226 Potential Energy *P8.20 When block B moves up by 1 cm, block A moves down by 2 cm and the separation becomes 3 cm. We then choose the final point to be when B has moved up by h 3 and has speed v A 2 . Then A has moved down 2 3 h and has speed v A : KKU mv m v mgh mg h mgh mv v gh g i g f AB A 2 A A 2 A ++ = ++= + F H G I K J +− = = ej 000 1 2 1 22 3 2 3 3 5 8 8 15 2 Section 8.3 Conservative and Nonconservative Forces P8.21 Fm g g == = 4 00 9 80 39 2 .. . kg m s N 2 bg (a) Work along OAC = work along OA + work along AC + ° =+ − =− FF gg OA AC N m m J af a f cos . cos 90 0 180 39 2 5 00 39 2 5 00 1 196 (b) W along OBC = W along OB + W along BC 39 2 5 00 180 39 2 5 00 90 0 196 c o s c o s . m m J O B A C (5.00, 5.00) m x y FIG. P8.21 (c) Work along OC F g OC cos135 F H G I K J 39 2 5 00 2 1 2 196 m J a f The results should all be the same, since gravitational forces are conservative.
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## This note was uploaded on 12/14/2011 for the course PHY 203 taught by Professor Staff during the Fall '11 term at Indiana State University .

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