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Unformatted text preview: homework 01 FIERRO, JEFFREY Due: Jan 18 2008, 11:00 pm 1 Question 1, chap 1, sect 1. part 1 of 2 10 points The rectangular and polar coordinates of a point are ( x, y ) and ( r, ), where x = 8 and = 23 . Determine the value of r. Correct answer: 8 . 69088 (tolerance 1 %). Explanation: The relation between rectangular and polar coordinates is: x = r cos y = r sin solving for r, r = x cos and y = r sin = x sin cos Question 2, chap 1, sect 1. part 2 of 2 10 points Determine the value of y. Correct answer: 3 . 3958 (tolerance 1 %). Explanation: Question 3, chap 1, sect 4. part 1 of 3 10 points Are all molecules of a particular substance alike? 1. Yes correct 2. No Explanation: Molecules are the smallest division that a substance can be divided into without chang ing its physical properties. Molecules are alike in their makeup and shape. They can bend slightly and flex, but always around a standard. Question 4, chap 1, sect 4. part 2 of 3 10 points Can molecules be broken into parts? 1. Yes correct 2. No Explanation: Molecules are clumps of atoms. In chemical reactions molecules can rearrange and break apart. Question 5, chap 1, sect 4. part 3 of 3 10 points How big are molecules? 1. around 10 10 meters in scale correct 2. around 10 6 meters in scale 3. around 10 2 meters in scale 4. around 10 2 meters in scale Explanation: The size of molecules are highly depen dent on the molecule. The smallest molecules are 10 10 meters in scale, and almost all are smaller than 10 6 meters in any dimension. Question 6, chap 1, sect 6. part 1 of 2 0 points The Statue of Liberty weighs nearly 205 tons. If a person can pull an average of 80 kg / person, how many people would it take to move the Statue of Liberty? Correct answer: 2563 (tolerance 1 %). Explanation: Let : w = 205 tons and R = 80 kg / person . Apply dimensional analysis: 205 tons 80 kg / person 1000 kg 1 ton = 2563 people . homework 01 FIERRO, JEFFREY Due: Jan 18 2008, 11:00 pm 2 Question 7, chap 1, sect 6. part 2 of 2 10 points The weight of the space shuttle is about 4 . 5 million pounds. How many people would it take to move it? Correct answer: 25569 (tolerance 1 %). Explanation: Let : w = 4 . 5 10 6 lb . 4 . 5 10 6 lb 80 kg / person 1 kg 2 . 2 lb 1 80 kg / person = 25569 people . So it would take about 25569 people to move the Statue of Liberty. Question 8, chap 1, sect 6. part 1 of 1 10 points Identify the equation below which is dimen sionally incorrect . A, x, y and r have units of length. k here has units of inverse length. v and v have units of velocity. a and g have units of acceleration....
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This note was uploaded on 04/03/2008 for the course PHY 303K taught by Professor Turner during the Spring '08 term at University of Texas at Austin.
 Spring '08
 Turner
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