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Unformatted text preview: mitchell (jm56986) HW #9 montgomery (24131) 1 This print-out should have 20 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points Why do ice cubes float? 1. Ice cubes are less dense than water. cor- rect 2. Ice cubes are lighter than water. 3. Ice cubes are in a solid state. Explanation: Ice cubes are less dense than water. If ice were more dense than water, it would sink, and the bottom of ponds and oceans could be covered by ice during the winter. 002 10.0 points Which situation is likely to hurt you more? 1. Your bare foot was stepped on by a 130-lb woman wearing high heels. correct 2. Your bare foot was stepped on by a 270-lb man wearing flat-soled loafer. 3. Either 4. Unable to determine Explanation: P = F A Pressure increases for a given force when the area decreases. 003 10.0 points What is the pressure if a force of 200 N is applied over an area of 50 cm 2 ? 1. 150 N/cm 2 2. 4 N/cm 2 correct 3. 10000 N/cm 2 4. 0.24 N/cm 2 Explanation: Let : F = 200 N and A = 50 cm 2 . P = F A = 200 N 50 cm 2 = 4 N/cm 2 . 004 10.0 points Put the following heights in the order of air density with the most dense point first: A) Earth surface B) low atmosphere (just above high moun- tains) C) high atmosphere (way above jet flights) D) deep mine E) the bottom of an imaginary hole drilled to the center of the Earth 1. DACEB 2. ABDEC 3. EDABC correct 4. DAEBC 5. DACBE 6. ABDCE Explanation: The air filling up the mine adds weight and pressure at the bottom of the mine, so the density of air in a deep mine is greater than that at the surface. (According to Boyles law, greater pressure in a gas means greater density.) 005 10.0 points Fluids are 1. either liquids or gases. correct 2. liquids, gases, and solids. mitchell (jm56986) HW #9 montgomery (24131) 2 3. liquids. 4. either solids or gases. Explanation: 006 10.0 points If you mixed oil and vinegar in one container, which would you expect to end up on top?...
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This note was uploaded on 11/22/2009 for the course PHYS 24131 taught by Professor Montogomery during the Fall '09 term at Northwest MS.
- Fall '09