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# awe-inspiring Great Pyramid of Cheops was built more than ISBN: 9780130606204 3

## Solution for problem 58PE Chapter 7

Physics: Principles with Applications | 6th Edition

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Problem 58PE

awe-inspiring Great Pyramid of Cheops was built more than 4500 years ago. Its square base, originally 230 m on a side, covered 13.1 acres, and it was 146 m high, with a mass of about 7×109 kg . (The pyramid’s dimensions are slightly different today due to quarrying and some sagging.) Historians estimate that 20,000 workers spent 20 years to construct it, working 12-hour days, 330 days per year. (a) Calculate the gravitational potential energy stored in the pyramid, given its center of mass is at one-fourth its height. (b) Only a fraction of the workers lifted blocks; most were involved in support services such as building ramps (see Figure 7.45), bringing food and water, and hauling blocks to the site. Calculate the efficiency of the workers who did the lifting, assuming there were 1000 of them and they consumed food energy at the rate of 300 kcal/h. What does your answer imply about how much of their work went into block-lifting, versus how much work went into friction and lifting and lowering their own bodies? (c) Calculate the mass of food that had to be supplied each day, assuming that the average worker required 3600 kcal per day and that their diet was 5% protein, 60% carbohydrate, and 35% fat. (These proportions neglect the mass of bulk and nondigestible materials consumed.)

Step-by-Step Solution:

Step-by-step solution Step 1 of 10 The formula to find the gravitational potential is, Here is the mass, is the acceleration due to gravity and is the height. Step 2 of 10 (a) Use the above formula, Substitute for , for and for . Step 3 of 10 Therefore, the gravitational potential energy is . Step 4 of 10 (b) The formula to find the energy is, Substitute for , for and for . Step 5 of 10 The formula to find the efficiency is,

Step 6 of 10

Step 7 of 10

##### ISBN: 9780130606204

This full solution covers the following key subjects: mass, food, calculate, workers, its. This expansive textbook survival guide covers 35 chapters, and 3914 solutions. The full step-by-step solution to problem: 58PE from chapter: 7 was answered by , our top Physics solution expert on 03/03/17, 03:53PM. Since the solution to 58PE from 7 chapter was answered, more than 405 students have viewed the full step-by-step answer. The answer to “awe-inspiring Great Pyramid of Cheops was built more than 4500 years ago. Its square base, originally 230 m on a side, covered 13.1 acres, and it was 146 m high, with a mass of about 7×109 kg . (The pyramid’s dimensions are slightly different today due to quarrying and some sagging.) Historians estimate that 20,000 workers spent 20 years to construct it, working 12-hour days, 330 days per year. (a) Calculate the gravitational potential energy stored in the pyramid, given its center of mass is at one-fourth its height. (b) Only a fraction of the workers lifted blocks; most were involved in support services such as building ramps (see Figure 7.45), bringing food and water, and hauling blocks to the site. Calculate the efficiency of the workers who did the lifting, assuming there were 1000 of them and they consumed food energy at the rate of 300 kcal/h. What does your answer imply about how much of their work went into block-lifting, versus how much work went into friction and lifting and lowering their own bodies? (c) Calculate the mass of food that had to be supplied each day, assuming that the average worker required 3600 kcal per day and that their diet was 5% protein, 60% carbohydrate, and 35% fat. (These proportions neglect the mass of bulk and nondigestible materials consumed.)” is broken down into a number of easy to follow steps, and 222 words. Physics: Principles with Applications was written by and is associated to the ISBN: 9780130606204. This textbook survival guide was created for the textbook: Physics: Principles with Applications, edition: 6.

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