Resolução Hallyday vol 2 c...ulo 14, 15, 16, 18, 19 e20 - exercicio (78), Manuais, Projetos, Pesquisas de Engenharia Física

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78. To be as general as possible, we denote the ratio of body density to water density as f (so that f= pip, = 0.95 in this problem). Floating involves equilibrium of vertical forces acting on the body (Earth”s gravity pulls down and the buoyant force pushes up). Thus. FF > psh=per where Vis the total volume of the body and V is the portion of it which is submerged. (a) We rearrange the above equation to yield HP sf Vo, which means that 95% of the body is submerged and therefore 5.0% is above the water surface (b) We replace py with 1.6, in the above equilibrium of forces relationship. and find Vo which means that 59% of the body is submerged and thus 41% is above the quicksand surface (e) The answer to part (b) suggests that a person in that situation is able to breathe.