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Unformatted text preview: reddy (ar38357) – Work and Energy – clancy – (SCI4112) 1 This printout should have 5 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 10.0 points Pete slides a crate up a ramp at an angle of 20 ◦ by exerting a 177 N force parallel to the ramp. The crate moves at a constant speed. The coefficient of friction is 0 . 4. How much work did Pete do when the crate was raised a vertical distance of 1 . 34 m? Correct answer: 693 . 468 J. Explanation: Let : F = 177 N , θ = 20 ◦ , μ = 0 . 4 , and h = 1 . 34 m . Let ℓ be the length of the plane and h be its height. The sine of the angle θ is sin θ = h ℓ Pete exerts a force F for a distance ℓ = h sin θ , so the work he does is W = F ℓ = F h sin θ = (177 N) parenleftbigg 1 . 34 m sin 20 ◦ parenrightbigg = 693 . 468 J . 002 10.0 points When you try to stretch a bungee cord a distance x , it resists with an opposing force of the form b x 2 , where b is a constant. If b is measured to be 6 N/m 2 , how much work does it take to stretch the bungee cord a distance of 1 meter?...
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 Fall '10
 Sontar
 Physics, Energy, Velocity, m/s, Joule, vxi

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