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Unformatted text preview: huynh (hph268) – HW #4 – clark – (56485) 1 This print-out should have 19 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points Two identical objects are moving directly to- ward one another at the same speed v . vectorv- vectorv m m What is the total kinetic energy of the sys- tem of the two objects? 1. Zero since ( vectorv- vectorv ) 2 = 0 2. None of these 3. 4 mv 2 since (2 v ) 2 = 4 v 2 4. Still 1 2 mv 2 from the definition of kinetic energy 5. mv 2 since energy is a scalar 002 10.0 points An object with mass M is attached to the end of a string and is being lowered vertically at a constant acceleration of g 6 . If it has been lowered a distance ℓ from rest, how much work has been done by the tension in the string? 1. M g ℓ 6 2.- M g ℓ 6 3.- M g ℓ 3 4.- 5 M g ℓ 6 5. M g ℓ 3 6.- M g ℓ 7. M g ℓ 8. 5 M g ℓ 6 003 10.0 points A force F is exerted by a broom handle on the head of the broom, which has a mass m . The handle is at an angle θ to the horizontal, as shown below. F θ What is the work done by the force on the head of the broom as it moves a distance d across a horizontal floor? 1. W = F m tan θ 2. W = F d sin θ 3. W = F m cos θ 4. W = F md sin θ 5. W = F d cos θ 004 10.0 points A block of mass m is pushed a horizontal dis- tance D from position A to position B, along a horizontal plane with friction coefficient μ . Then m is pushed from B to A. If the force pushing m from A to B is vector P , and the force pushing m from B to A is- vector P , what is the total work done by friction?...
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This note was uploaded on 09/28/2011 for the course PH 303K taught by Professor Zao during the Spring '11 term at University of Texas.
- Spring '11