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Unformatted text preview: e conservation of energy requires that Ko + Uo = Uo = Kl Ul; or mg(l-cosOo) = !mv~ + mga(l - cos 01) (as in Example 8-6). When these results are combined, v~ = 2g(I- cos 00) - 2ga(1 - cosOd ~ -gacosOl, or cos8l ~ (2e/3a) (cos 00 -1 + a/f), which is the limiting value stated. If 00 90 and a then 01 = cos-l X [~ .~(O -1 + ~)] cos-Ie-I) == 180; i.e., the rope is taut at the top of the small circle: = + Problem 78 Solution. = = = if, Problem
79. Together, the springs in a 120<hkg car llave an effective spring constant of 110,000 N lin and can compress a maximum distance of 40 What is the maximum abrupt drop inroad level (Fig. 8-48) that the car can tolerate without "bottoming out"-that is, without its springs reaching maximum compression? Assume the car is driving fast enough that it becomes temporaI'ilyairborne. Problem
81. AD electron with kinetic energy 0.85 fJ enters a region where its potential energy as a function of 2 position is U ax2 - bx, where a = 2.7 fJ/cm and b = 4.2 fJjcm. (a) How far into the region does the el...
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