1296_Physics ProblemsTechnical Physics

1296_Physics ProblemsTechnical Physics - Chapter 46 P46.44...

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Chapter 46 637 P46.44 The density of the Universe is ρρ π == F H G I K J 120 3 8 2 .. c H G . Consider a remote galaxy at distance r . The mass interior to the sphere below it is Mr H G r Hr G = F H G I K J = F H G I K J F H G I K J = ρπ 4 3 3 8 4 3 0600 3 2 3 23 . . both now and in the future when it has slowed to rest from its current speed vH r = . The energy of this galaxy-sphere system is constant as the galaxy moves to apogee distance R : 1 2 0 2 mv GmM r GmM R −= so 1 2 0 22 mH r Gm r G Gm R G F H G I K J =− F H G I K J 0 100 0 600 r R so Rr = 600 The Universe will expand by a factor of . from its current dimensions. P46.45 (a) kT mc p B 2 2 so T k p ≈= × × F H G I K J 2 29383 138 10 160 10 10 2 23 13 13 B MeV JK J 1 MeV K . . . ~ af ej (b) e B 2 2 so T k e × × F H G I K J 2 20511
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This note was uploaded on 12/15/2011 for the course PHY 203 taught by Professor Staff during the Fall '11 term at Indiana State University .

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