College Physics: A Strategic Approach (4th Edition)
4th Edition
ISBN: 9780134609034
Author: Randall D. Knight (Professor Emeritus), Brian Jones, Stuart Field
Publisher: PEARSON
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Chapter 11, Problem 7CQ
For most automobiles, the number of miles per gallon decreases as highway speed increases. Fuel economy drops as speeds increase from 55 to 65 mph, then decreases further as speeds increase to 75 mph. Explain why this is the case.
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Electric vehicles increase speed by using an electric motor that draws energy from a battery. When the vehicle slows, the motor runs as a generator, recharging the battery. Explain why this means that an electric vehicle can be more efficient than a gasoline-fueled vehicle.
For most automobiles, the number of miles per gallon decreases as highway speed increases. Fuel economy drops as speeds increase from 55 to 65 mph, then decreases further as speeds increase to 75 mph. Explain why this is the case.
Q20:
Dr. Fahrrad has been riding his bike to his job and is curious how many ATP his body is breaking apart in order to do the work required to get to his job.
Dr. Fahrrad rides 8.6 kilometers to his job, has a mass of 68.4 kilograms and has an average acceleration of 2.4 kilometers per second squared.
The molecule ATP is able to do work, measured in kilojoules per mole of ATP broken into ADP. The SI unit for work is a joule. Using the information given we can calculate work and then convert to moles of ATP.
The first step is to take stock of what we are given in the word problem and what we are trying to find. We have mass, distance, and average acceleration. We are trying to find how many ATP are required to power the bike ride to work.
The equation for work, is force times distance and will tell us how many joules Dr. Farrhad is using on his bike ride. It also incorporates one of our given variables, distance. However, the distance was reported in kilometers and the SI unit of…
Chapter 11 Solutions
College Physics: A Strategic Approach (4th Edition)
Ch. 11 - Rub your hands together vigorously. What happens?...Ch. 11 - Describe the energy transfers and transformations...Ch. 11 - According to Table 11.4, cycling at 15 km/h...Ch. 11 - Prob. 4CQCh. 11 - Prob. 5CQCh. 11 - For most automobiles, the number of miles per...Ch. 11 - Prob. 8CQCh. 11 - Prob. 9CQCh. 11 - Prob. 10CQCh. 11 - Prob. 11CQ
Ch. 11 - Prob. 12CQCh. 11 - For Questions 12 through 17, give a specific...Ch. 11 - For Questions 12 through 17, give a specific...Ch. 11 - For Questions 12 through 17, give a specific...Ch. 11 - For Questions 12 through 17, give a specific...Ch. 11 - For Questions 12 through 17, give a specific...Ch. 11 - For Questions 12 through 17, give a specific...Ch. 11 - Prob. 19CQCh. 11 - Prob. 20CQCh. 11 - Prob. 21CQCh. 11 - Prob. 22CQCh. 11 - Prob. 24CQCh. 11 - Prob. 25CQCh. 11 - Electric vehicles increase speed by using an...Ch. 11 - When the suns light hits the earth, the...Ch. 11 - Prob. 29CQCh. 11 - Prob. 30CQCh. 11 - Prob. 31CQCh. 11 - Prob. 32MCQCh. 11 - Prob. 33MCQCh. 11 - A person is walking on level ground at constant...Ch. 11 - A person walks 1 km, turns around, and runs back...Ch. 11 - 200 J of heat is added to two gases, each in a...Ch. 11 - Prob. 37MCQCh. 11 - A refrigerators freezer compartment is set at 10C;...Ch. 11 - A 10% efficient engine accelerates a 1500 kg car...Ch. 11 - Prob. 2PCh. 11 - A typical photovoltaic cell delivers 4.0 103 W of...Ch. 11 - Prob. 4PCh. 11 - Prob. 5PCh. 11 - Prob. 6PCh. 11 - In an average human, basic life processes require...Ch. 11 - Prob. 8PCh. 11 - An energy bar contains 22 g of carbohydrates. How...Ch. 11 - Prob. 10PCh. 11 - Prob. 11PCh. 11 - Prob. 12PCh. 11 - An energy bar contains 22 g of carbohydrates. If...Ch. 11 - Prob. 14PCh. 11 - Prob. 15PCh. 11 - Prob. 16PCh. 11 - The label on a candy bar says 400 Calories....Ch. 11 - Prob. 18PCh. 11 - A weightlifter curls a 30 kg bar, raising it each...Ch. 11 - Prob. 20PCh. 11 - Prob. 21PCh. 11 - Prob. 22PCh. 11 - Suppose your body was able to use the chemical...Ch. 11 - Prob. 24PCh. 11 - Prob. 25PCh. 11 - Prob. 26PCh. 11 - Prob. 27PCh. 11 - The planet Mercurys surface temperature varies...Ch. 11 - A piece of metal at 100C has its Celsius...Ch. 11 - Prob. 30PCh. 11 - 500 J of work are done on a system in a process...Ch. 11 - Prob. 32PCh. 11 - 600 J of heat energy are transferred to a system...Ch. 11 - 10 J of heat are removed from a gas sample while...Ch. 11 - A heat engine extracts 55 kJ from the hot...Ch. 11 - A heat engine does 20 J of work while exhausting...Ch. 11 - A power plant running at 35% efficiency generates...Ch. 11 - A heat engine operating between energy reservoirs...Ch. 11 - A newly proposed device for generating electricity...Ch. 11 - Prob. 41PCh. 11 - Prob. 42PCh. 11 - Prob. 43PCh. 11 - Prob. 44PCh. 11 - A refrigerator takes in 20 J of work and exhausts...Ch. 11 - Air conditioners are rated by their coefficient of...Ch. 11 - 50 J of work are done on a refrigerator with a...Ch. 11 - Prob. 48PCh. 11 - Find the maximum possible coefficient of...Ch. 11 - Prob. 50PCh. 11 - Prob. 51PCh. 11 - Prob. 52PCh. 11 - Prob. 53PCh. 11 - Prob. 55GPCh. 11 - Prob. 56GPCh. 11 - The record time for a Tour de France cyclist to...Ch. 11 - Championship swimmers take about 22 s and about 30...Ch. 11 - A 68 kg hiker walks at 5.0 km/h up a 7% slope....Ch. 11 - To make your workouts more productive, you can get...Ch. 11 - The resistance of an exercise bike is often...Ch. 11 - Prob. 62GPCh. 11 - Prob. 63GPCh. 11 - An engine does 10 J of work and exhausts 15 J of...Ch. 11 - An engine operating at maximum theoretical...Ch. 11 - An engineer claims to have measured the...Ch. 11 - A typical coal-fired power plant burns 300 metric...Ch. 11 - Prob. 68GPCh. 11 - Air conditioners sold in the United States are...Ch. 11 - The surface waters of tropical oceans are at a...Ch. 11 - The light energy that falls on a square meter of...Ch. 11 - Prob. 72MSPPCh. 11 - Prob. 73MSPPCh. 11 - Prob. 74MSPPCh. 11 - Prob. 75MSPPCh. 11 - Prob. 76MSPPCh. 11 - Prob. 77MSPPCh. 11 - Prob. 78MSPPCh. 11 - Prob. 79MSPP
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