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Unformatted text preview: hernandez (ejh742) oldhomework 29 Turner (58120) 1 This print-out should have 12 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points The force required to stretch a spring varies directly with the amount the spring is stretched. A spring stretches by 79 m when a 63 N weight is hung from it and the weight is at rest (at equilibrium). The 63 N weight is replaced by an unknown weight W so that the spring is stetched to a new equilibrium position, 55 m below the position if no weight were attached. The weight W is then dis- placed from equilibrium and released so that it oscillates. 55 m 79 m W 63 N Calculate the period of motion. The accel- eration of gravity is 9 . 8 m / s 2 . Correct answer: 14 . 885 N. Explanation: Let : W = W , W = 63 N , x 1 = 55 m , and x 2 = 79 m . F = k x , so W W = x 1 x 2 m 1 g W = x 1 x 2 m 1 = W x 1 g x 2 = (63 N)(55 m) (9 . 8 m / s 2 )(79 m) = 4 . 47559 kg = radicalbigg k m 1 , so the (angular) frequency of os- cillation is T = 2 = 2 radicalbigg m 1 k = 2 radicalBigg 4 . 47559 kg . 797468 N / m = 14 . 885 s . 002 10.0 points You are designing a pendulum clock to have a period of 1.0 s. The acceleration of gravity is 9 . 81 m / s 2 . How long should the pendulum be? Correct answer: 0 . 24849 m....
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