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Unformatted text preview: markowitz (am45362) – HW01 – distler – (56295) 1 This printout should have 22 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 (part 1 of 4) 10.0 points One cubic centimeter ( 1 cm 3 ) of water has a mass of 0 . 001 kg at 25 ◦ C. Find the mass of 2 . 85 m 3 of water. Correct answer: 2850 kg. Explanation: Let : V = 2 . 85 m 3 and ρ = . 001 kg 1 cm 3 . ρ = m V m = ρ V = parenleftbigg . 001 kg 1 cm 3 parenrightbigg (2 . 85 m 3 ) parenleftbigg 100 cm 1 m parenrightbigg 3 = 2850 kg . 002 (part 2 of 4) 10.0 points Assume biological substances are 95 . 1% wa ter. Estimate the mass of a cell assuming it to be spherical with a diameter of 1 . 74 μ m. The volume of a sphere is 4 3 π r 3 . Correct answer: 2 . 75833 × 10 − 15 kg. Explanation: Let : ρ = 1 . × 10 3 kg / m 3 and r = 0 . 87 μ m = 8 . 7 × 10 − 7 m . Assume 100% of the total mass: ρ = m V m = ρ V = ρ 4 3 π r 3 = ( 1000 kg / m 3 ) 4 3 π ( 8 . 7 × 10 − 7 m ) 3 = 2 . 75833 × 10 − 15 kg . 003 (part 3 of 4) 10.0 points Estimate the mass of a human kidney if it is roughly a sphere with a radius of 4 . 01 cm. Correct answer: 0 . 270098 kg. Explanation: Let : r = 4 . 01 cm = 0 . 0401 m . Assume 100% of the total mass: m = ρ V = ρ 4 3 π r 3 = ( 1000 kg / m 3 ) 4 3 π (0 . 0401 m) 3 = . 270098 kg . 004 (part 4 of 4) 10.0 points Estimate the mass of a fly, roughly a cylinder 4 . 42 mm long and 1 . 71 mm in diameter. The volume of a cylinder is π r 2 ℓ . Correct answer: 1 . 01509 × 10 − 5 kg. Explanation: Let : ρ = 1 . × 10 3 kg / m 3 , r = 0 . 855 mm = 0 . 000855 m , and ℓ = 4 . 42 mm = 0 . 00442 m . The volume is V = π r 2 ℓ . Estimate 100% of the total mass: m = ρ V = ρ π r 2 ℓ = ( 1000 kg / m 3 ) π (0 . 000855 m) 2 × (0 . 00442 m) = 1 . 01509 × 10 − 5 kg ....
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 Fall '08
 Kaplunovsky

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