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Unformatted text preview: approximate as occurring when r R = e t /h = 0 . 05 Taking the natural log of both sides of this equation, we find t h 3 = t 3 h (a) For a missile with the given values, the spinup time is t = 3(2 m) (1 . 5 10 6 m 2 / sec) (10 sec 1 ) = 1549 sec . = 26 min (b) For an experiment with the given values, the spinup time is t = 3(3 . 5 in)(1 / 12 ft / in) 5 p 1 . 08 10 5 ft 2 / sec Q (120 rpm) (2 / 60 sec 1 / rpm) = 75 sec (c) Solving for from the equation derived above, = 1 X 3 h t ~ 2 10.12. CHAPTER 10, PROBLEM 12 1333 Denoting the observed spinup time by t true , there follows e f = w t t true W 2 Hence, for the observed time of t true = 2 . 5 sec, we have e f = w 75 sec 2 . 5 sec W 2 = 900...
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 Spring '06
 Phares

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