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Unformatted text preview: Version One – Homework 6 – savrasov – 39822 – Nov 05, 2007 1 This printout should have 8 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. The due time is Central time. Inelastic Collision of Cars 09:06, trigonometry, numeric, > 1 min, nor mal. 001 (part 1 of 1) 2 points A car with mass 1245 kg, moving at 29 m / s, strikes a(n) 2175 kg car at rest. If the two cars stick together, with what speed do they move? Correct answer: 10 . 557 m / s. Explanation: Basic concepts Momentum of any object is p = mv The collision is inelastic, and by conservation of momentum, p before = p after m 1 v o + 0 = ( m 1 + m 2 ) v f v f = m 1 v o ( m 1 + m 2 ) keywords: Water Fills a Bucket 09:06, trigonometry, numeric, > 1 min, nor mal. 002 (part 1 of 1) 2 points Water ( ρ = 1000 kg / m 3 ) falls without splash ing at a rate of 0 . 25 L / s from a height of 60 m into a 0 . 75 kg bucket on a scale. The acceleration of gravity is 9 . 8 m / s 2 . If the bucket is originally empty, what does the scale read after 3 s ? Correct answer: 23 . 2732 N. Explanation: From conservation of energy, the velocity is m g h = 1 2 m v 2 v = p 2 g h = q 2 (9 . 8 m / s 2 ) (60 m) = 34 . 2929 m / s . u is the volume rate of the flow, so the mass rate of the flow is u m = ρ u = (1000 kg / m 3 )(0 . 25 L / s) µ 1 m 100 cm ¶ 3 × 1000 cm 3 1 L = 0 . 25 kg / s ....
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This note was uploaded on 01/10/2010 for the course PHY na taught by Professor Richardscalettar during the Fall '09 term at UC Davis.
 Fall '09
 RichardScalettar
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