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Unformatted text preview: Create assignment, 00223, Homework 8, Nov 04 at 12:57 pm 1 This printout should have 11 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. The due time is Central time. Net Torque on a Wheel 10:07, trigonometry, numeric, > 1 min, wordingvariable. 001 A circular shaped object has an inner radius of 12 m and an outer radius of 25 m. Three forces (acting perpendicular to the axis of ro tation) of magnitudes 11 N, 24 N, and 14 N act on the object, as shown. The force of magnitude 24 N is 31 below horizontal. 11 N 14 N 24 N 11 kg 31 12 m 25 m Find the magnitude of the net torque on the wheel about the axle through the center of the object. Correct answer: 3 . 37 Nm. Explanation: Let : a = 12 m , b = 25 m , F 1 = 11 N , F 2 = 24 N , F 3 = 14 N , and = 31 . F 1 F 3 F 2 M a b The total torque is = a F 2 b F 1 b F 3 = (12 m)(24 N) (25 m) h (11 N) + (14 N) i = 3 . 37 Nm k ~ k = 3 . 37 Nm . keywords: Blocks and a Wedge 10:08, trigonometry, numeric, > 1 min, nor mal. 002 A block of mass 2 kg and one of mass 6 kg are connected by a massless string over a pul ley that is in the shape of a disk having a radius of 0 . 25 m, and a mass of 9 kg. In addi tion, the blocks are allowed to move on a fixed blockwedge of angle = 30 , as shown. The coefficient of kinetic friction is 0 . 27 for both blocks. 2 kg 6 k g 30 . 25 m 9 kg Determine the acceleration of the two blocks. The acceleration of gravity is 9 . 8 m / s 2 . Assume: The positive direction is to the right. Correct answer: 0 . 828719 m / s 2 . Explanation: Let : m 1 = 2 kg , m 2 = 6 kg , M = 9 kg , and R = 0 . 25 m . Newtons second low is X ~ F = m~a Create assignment, 00223, Homework 8, Nov 04 at 12:57 pm 2 For m 1 N 1 m 1 g = m 1 a y = 0 N 1 = m 1 g and the force of friction is then f 1 = N 1 = (0 . 27)(2 kg)(9 . 8 m / s 2 ) = 5 . 292 N ....
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This note was uploaded on 05/06/2011 for the course PHYS 103N taught by Professor Chiu during the Spring '11 term at University of Texas at Austin.
 Spring '11
 Chiu
 Physics, Work

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