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Unformatted text preview: Busto, Anthony – Homework 9 – Due: Nov 10 2006, 11:00 pm – Inst: Opyrchal, H 1 This printout should have 9 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. The due time is Central time. 001 (part 1 of 1) 10 points An electric motor rotating a workshop grind ing wheel at a rate of 202 rev / min is switched off. Assume constant angular deceleration of magnitude 2 . 1 rad / s 2 . Through how many revolutions does the wheel turn before it fi nally comes to rest? Correct answer: 16 . 9563 rev. Explanation: From the formula ω 2 = ω 2 + 2 αθ and solving for θ we obtain θ = ω 2 2 α Note that 2 π rad = 1 rev. keywords: 002 (part 1 of 1) 10 points The driver of a car traveling at 22 . 4 m / s ap plies the brakes and undergoes a constant deceleration of 2 . 72 m / s 2 . How many revolutions does each tire make before the car comes to a stop, assuming that the car does not skid and that the tires have radii of 0 . 388 m? Correct answer: 37 . 8343 rev. Explanation: Basic Concepts v = rω a = rα ω 2 = ω 2 + 2 αθ The deceleration of the rim of each tire is 2 . 72 m / s 2 , so the angular acceleration of each wheel is given by α = a r = 2 . 72 m / s 2 . 388 m = 7 . 01031 rad / s 2 ....
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 Spring '08
 moro
 Physics, Work, Moment Of Inertia, kg, Physical quantities, Icm

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