Unformatted text preview: cylinder? According to Archimedes’ principle, the buoyancy on the cylinder is equal to the weight of water displaced by the cylinder. Since 1.5 cm is above the surface of water, the rest 6.5 cm is under the surface of water. The buoyancy is B C = ρ W (6.5/8)(Ah)g = 1.59 N b) What is the radius r of the lead ball? Newton’s 2 nd law applied to the whole system yields B B + B C – W B – W C = 0 We express the buoyancies and gravitational forces in terms of volumes and densities and solve the equation for the volume of the ball. ρ W V B g + ρ W (6.5/8)(Ah)g – ρ B V B g – ρ Ahg = 0 ⇒ V B = [(6.5/8) ρ W – ρ C ]Ah/( ρ B – ρ W ) = 7.93 cm 3 The radius of the ball is V B = (4 π /3)r 3 r = 3 √ (3V B /(4 π )) = 1.24 cm...
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 Summer '08
 Field
 Work, upright cylinder, lead ball, Tomoyuki Nakayama

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