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Unformatted text preview: yoon (jy4326) HW06 markert (58840) 1 This print-out should have 21 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 (part 1 of 2) 10.0 points A rock of mass m is thrown horizontally off a building from a height h . The speed of the rock as it leaves the throwers hand at the edge of the building is v as shown. v h x How much time does it take the rock to travel from the edge of the building to the ground? 1. t = 2 h g 2. t = radicalBigg 2 h g correct 3. t = hv g 4. t = radicalbig hv 5. t = h v Explanation: The motion of the rock in the y-direction is a free falling motion from rest: h = 1 2 g t 2 t = radicalBigg 2 h g . 002 (part 2 of 2) 10.0 points What is the kinetic energy of the rock just before it hits the ground? 1. K f = mg h- 1 2 mv 2 2. K f = mg h 3. K f = 1 2 mv 2 + mg h correct 4. K f = 1 2 mv 2 5. K f = 1 2 mv 2- mg h Explanation: By the work-energy theorem, K f- K i = W , where in the present problem, W = ( mg ) h and K i = 1 2 mv 2 . Thus, K f = K i + W = 1 2 mv 2 + mg h . 003 (part 1 of 4) 10.0 points Part 3: minimum speed (excluding position O) A bead slides starting from rest at position O on a frictionless wire. The gravitation field is in the- y direction. x y Y Z S O At which position(s) will the speed of the bead have a maximum value? 1. Point S . correct 2. Points Y and S . 3. Point Y . 4. The bead remains stationary at point O . 5. Point Z . Explanation: Since the total energy is constant, the max- imum kinetic energy will occur when the po- tential energy is a minimum. Thus point S is yoon (jy4326) HW06 markert (58840) 2 the correct answer. 004 (part 2 of 4) 10.0 points At which position(s) will the magnitude of the acceleration in the x direction of the bead have a maximum value? 1. Points Y and S . 2. Point Z . 3. Point S . 4. Point O . correct 5. Point Y . Explanation: The acceleration is maximum at point O . The acceleration is along the path of the wire at point O . Therefore the x component of the acceleration is greatest at point O . 005 (part 3 of 4) 10.0 points At which position(s) will the speed of the bead have a minimum value?...
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This note was uploaded on 01/08/2010 for the course CH 53675 taught by Professor Bocknack during the Fall '09 term at University of Texas.
- Fall '09
- Organic chemistry