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Unformatted text preview: fullwood (tf5349) – QUIZ 8 Work and Energy – Catala – (49033) 1 This print-out should have 5 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 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 thrower’s hand at the edge of the building is v , as shown. m h v m 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- mg h 5. K f = 1 2 mv 2 Explanation: We can use 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 . Comments for Matter Interaction readers: The energy principle in MI-text is referred to as the work-energy theorem in traditional text. Here the work done by the gravitational force near the surface of the earth is given by: W = (- mg )(...
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