EBK COLLEGE PHYSICS
3rd Edition
ISBN: 9780321989246
Author: Knight
Publisher: PEARSON CO
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Textbook Question
Chapter 11, Problem 52GP
A large horse can perform work at a steady rate of about 1 horsepower, as you might expect.
a. Assuming a 25% efficiency, how many Calories would a horse need to consume to work at 1.0 hp for 1.0 h?
b. Dry hay contains about 10 MJ per kg. How many kilograms of hay would the horse need to eat to perform this work?
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Students have asked these similar questions
A weightlifter works out at the gym each day. Part of her routine is to lie on her back and lift a 40 kg barbell straight up from chest height to full arm extension, a distance of 0.50 m.a. How much work does the weightlifter do to lift the barbell one time?b. If the weightlifter does 20 repetitions a day, what total energy does she expend on lifting, assuming a typical efficiency for energy use by the body.c. How many 400 Calorie donuts can she eat a day to supply that energy?
Question:
1. Suppose that the elevator is broken in the building n which you work and you
have to climb 9 stories.
-a height of 45m above ground level.
How many extra calories will this external work cost you if your mass is 70 kg and
your body work at 15% efficiency?
2. A 70 kg hiker climbed a mountain 1000 m high. He reached the peak in 3 hr.
A. Calculate the external work done by the climber.
B. Assuming the work was done at a steady rate during the 3 hr period.
Calculate the power generated durir
the climb.
C. Assuming the average O, consumption during he climb was 2 liters/min
(corresponding to 9.6 kcal/min), find the efficiency of the hiker's body.
D. How much energy appeared as heat in the body?
The food calorie, equal to 4186 JJ, is a measure of how much energy is released when food is metabolized by the body. A certain brand of fruit-and-cereal bar contains 145 food calories per bar.
A.
If a 71.0 kgkg hiker eats one of these bars, how high a mountain must he climb to "work off" the calories, assuming that all the food energy goes only into increasing gravitational potential energy?
Express your answer in meters. H=____________m
B.
If, as is typical, only 25.0 %% of the food calories go into mechanical energy, what would be the answer to part A? (Note: In this and all other problems, we are assuming that 100%% of the food calories that are eaten are absorbed and used by the body. This is actually not true. A person's "metabolic efficiency" is the percentage of calories eaten that are actually used; the rest are eliminated by the body. Metabolic efficiency varies considerably from person to person.)
Express your answer in meters.
H=______________m
Chapter 11 Solutions
EBK COLLEGE PHYSICS
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 - For most automobiles, the number of miles per...Ch. 11 - A glassblower heats up a blob of glass in a...Ch. 11 - When the space shuttle returns to earth, its...Ch. 11 - Prob. 8CQCh. 11 - Prob. 9CQCh. 11 - A 20 kg block of steel at 23C and a 150 g piece of...
Ch. 11 - Prob. 11CQCh. 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 - A fire pistonan impressive physics...Ch. 11 - Prob. 19CQCh. 11 - A drop of green ink falls into a beaker of clear...Ch. 11 - Prob. 21CQCh. 11 - Prob. 22CQCh. 11 - According to the second law of thermodynamics, it...Ch. 11 - Assuming improved materials and better processes,...Ch. 11 - Electric vehicles increase speed by using an...Ch. 11 - When the suns light hits the earth, the...Ch. 11 - When you put an ice cube tray filled with liquid...Ch. 11 - Prob. 28CQCh. 11 - A person is walking on level ground at constant...Ch. 11 - A person walks 1 km, turns around, and runs back...Ch. 11 - Prob. 31MCQCh. 11 - 200 J of heat is added to two gases, each in a...Ch. 11 - An inventor approaches you with a device that he...Ch. 11 - Prob. 34MCQCh. 11 - Prob. 35MCQCh. 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 - A fast-food hamburger (with cheese and bacon)...Ch. 11 - In an average human, basic life processes require...Ch. 11 - An energy bar contains 6.0 g of fat. How much...Ch. 11 - An energy bar contains 22 g of carbohydrates. How...Ch. 11 - Prob. 9PCh. 11 - An energy bar contains 22 g of carbohydrates. If...Ch. 11 - Suppose your body was able to use the chemical...Ch. 11 - The label on a candy bar says 400 Calories....Ch. 11 - A weightlifter curls a 30 kg bar, raising it each...Ch. 11 - Prob. 14PCh. 11 - Prob. 15PCh. 11 - The planet Mercurys surface temperature varies...Ch. 11 - A piece of metal at 100C has its Celsius...Ch. 11 - Prob. 18PCh. 11 - 500 J of work are done on a system in a process...Ch. 11 - 600 J of heat energy are transferred to a system...Ch. 11 - 300 J of energy are transferred to a system in the...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 heat engine does 200 J of work while exhausting...Ch. 11 - A heat engine with an efficiency of 40% does 100 J...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 - Converting sunlight to electricity with solar...Ch. 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 - Find the maximum possible coefficient of...Ch. 11 - Which, if any, of the heat engines in Figure...Ch. 11 - Which, if any, of the refrigerators in Figure...Ch. 11 - Prob. 37PCh. 11 - Prob. 38GPCh. 11 - Prob. 39GPCh. 11 - For how long would a 68 kg athlete have to swim at...Ch. 11 - a. How much metabolic energy is required for a 68...Ch. 11 - Prob. 42GPCh. 11 - Prob. 43GPCh. 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 - A 70 kg student consumes 2500 Cal each day and...Ch. 11 - To make your workouts more productive, you can get...Ch. 11 - The resistance of an exercise bike is often...Ch. 11 - Prob. 50GPCh. 11 - Prob. 51GPCh. 11 - A large horse can perform work at a steady rate of...Ch. 11 - A heat engine with a high-temperature reservoir at...Ch. 11 - An engine does 10 J of work and exhausts 15 J of...Ch. 11 - The heat exhausted to the cold reservoir of an...Ch. 11 - An engine operating at maximum theoretical...Ch. 11 - Some heat engines can run on very small...Ch. 11 - The coefficient of performance of a refrigerator...Ch. 11 - An engineer claims to have measured the...Ch. 11 - A 32% efficient electric power plant produces 900...Ch. 11 - A typical coal-fired power plant burns 300 metric...Ch. 11 - Each second, a nuclear power plant generates 2000...Ch. 11 - Prob. 63GPCh. 11 - Prob. 64GPCh. 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 - MCAT-Style Passage Problems Kangaroo Locomotion...Ch. 11 - MCAT-Style Passage Problems Kangaroo Locomotion...Ch. 11 - MCAT-Style Passage Problems Kangaroo Locomotion...Ch. 11 - MCAT-Style Passage Problems Kangaroo Locomotion...Ch. 11 - MCAT-Style Passage Problems Kangaroo Locomotion...
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