# HW7a - Version One Homework 7 savrasov 39822 Nov 13, 2007 1...

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Unformatted text preview: Version One Homework 7 savrasov 39822 Nov 13, 2007 1 This print-out should have 9 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. The due time is Central time. Serway CP 07 18 10:02, trigonometry, numeric, > 1 min, nor- mal. 001 (part 1 of 3) 1 points A race car starts from rest on a circular track of radius 400 m. The cars speed increases at the constant rate of 0 . 5 m / s 2 . At the point where the magnitudes of the radial and tangential accelerations are equal, determine the speed of the race car. Correct answer: 14 . 1421 m / s. Explanation: Given : r = 400 m , v i = 0m / s , and a t = 0 . 5 m / s 2 . a t = a c = v 2 f r v f = a t r = q (0 . 5 m / s 2 )(400 m) = 14 . 1421 m / s . 002 (part 2 of 3) 1 points Find the distance traveled at the same mo- ment. Correct answer: 200 m. Explanation: Linear and angular velocities are related by v = r . The velocity is given by v f 2 = v i 2 + 2 a t s = 2 a t s since v i = 0, so s = v f 2 2 a t = (14 . 1421 m / s) 2 2(0 . 5 m / s 2 ) = 200 m . 003 (part 3 of 3) 1 points Find the elapsed time at the same moment. Correct answer: 28 . 2843 s. Explanation: v f = v i + a t = a t since v i = 0, so t = v f a = 14 . 1421 m / s . 5 m / s 2 = 28 . 2843 s ....
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## This note was uploaded on 01/10/2010 for the course PHY na taught by Professor Richardscalettar during the Fall '09 term at UC Davis.

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HW7a - Version One Homework 7 savrasov 39822 Nov 13, 2007 1...

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