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Unformatted text preview: Gozick, Brandon – Homework 7 – Due: Oct 3 2006, 7:00 pm – Inst: D Weathers 1 This printout should have 8 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 2) 10 points An amusement park ride consists of a rotat ing circular platform 7 . 4 m in diameter from which 10 kg seats are suspended at the end of 1 . 3 m massless chains. When the system ro tates, the chains make an angle of 43 . 2 ◦ with the vertical. The acceleration of gravity is 9 . 8 m / s 2 . θ l d What is the speed of each seat? Correct answer: 6 . 49924 m / s. Explanation: In the vertical direction we have T cos θ = m g , where T is the tension in the chain. In the horizontal direction we have T sin θ = m v 2 r . Since r = ‘ sin θ + d 2 = (1 . 3 m)sin43 . 2 ◦ + 7 . 4 m 2 = 4 . 58991 m , we have v = p g r tan θ = q (9 . 8 m / s 2 )(4 . 58991 m)tan43 . 2 ◦ = 6 . 49924 m / s . 002 (part 2 of 2) 10 points If a child of mass 52 . 7 kg sits in a seat, what is the tension in the chain (for the same angle)? Correct answer: 842 . 917 N. Explanation: M = 52 . 7 kg From the first part we have T cos θ = ( m + M ) g T = ( m + M ) g cos θ = (10 kg + 52 . 7 kg)(9 . 8 m / s 2 ) cos43 . 2 ◦ = 842 . 917 N . keywords: 003 (part 1 of 1) 10 points A curve of radius 50 . 4 m is banked so that a car traveling with uniform speed 46 km / hr can round the curve without relying on fric tion to keep it from slipping to its left or right....
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This note was uploaded on 09/12/2008 for the course PHYS 1710 taught by Professor Weathers during the Fall '08 term at North Texas.
 Fall '08
 Weathers
 mechanics, Work

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