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Unformatted text preview: e ,,,,,,,voi, sits 140 m above its gstation and holds 8.5x 109 kg of water. \ver plant generates 330 MW of electric .Yh.ile draining the reservoir over an ieed-"""age FIGURE 8-38 Problem 55. 1l
I' II 136 CHAPTER 8 . Solution " of Vl when V2 = 0, or Vl,min = ";6.53 m2js2 ::::: The final kinetic energy, the initial p.ote~~ial energy of II the spring, and the change in the gravitational potential energy are all zero. Therefore, nc= -I-'Kmgx = 11K + 11U = + 0.51(100 N /m)(0.21 m)2 - (2.5 kg)(1.8 m/s)2J -1.85 J, or ILk = (1.85 J)/(2.5 kg)(9.8 m/s2)(O.21 in) = 0.36. 2.56 mfs. -~mv5 ~k.x~i,=
,i! W Problem
58. A biologist uses a spring-loaded dart gun to shoot a 50-g tranquilizing dart into an elephant 21 m away. The gun's spring has spring constant k 690 N/m and is pulled back 14 em to launch the dart. The dart embeds itself 2.2 em in the elephant. (a) What is the average stopping force exerted on the dart by the elephant's .flesh? (b) How long does'it take the dart to re...
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