A woman expends 95 kJ of energy in walking a kilometer. The energy is supplied by the metabolic breakdown of food intake and has a 35 percent efficiency. If the woman drives a car over the same distance, how much energy is used if the car gets 8.8 km per liter of gasoline (approximately 20 mi/gal)? The density of gasoline is 0.71 g/mL, and its enthalpy of combustion is 49 kJ/g. Enter your answer in scientific notation. Compare the efficiencies of the two processes. kJ (driving)/ kJ (walking)

A woman expends 95 kJ of energy in walking a kilometer. The energy is supplied by the metabolic breakdown of food intake and has a 35 percent efficiency. If the woman drives a car over the same distance, how much energy is used if the car gets 8.8 km per liter of gasoline (approximately 20 mi/gal)? The density of gasoline is 0.71 g/mL, and its enthalpy of combustion is 49 kJ/g. Enter your answer in scientific notation. Compare the efficiencies of the two processes. kJ (driving)/ kJ (walking)

College Physics

10th Edition

ISBN:9781285737027

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter1: Introduction

Section: Chapter Questions

Problem 20P: A certain car has a fuel efficiency of 25.0 miles per gallon (mi/gal). Express this efficiency in...

See similar textbooks

Similar questions

A particular frost-free refrigerator uses about 720 kWh of electrical energy per year. Express this amount of energy in joules (J). Express this amount of energy in kilojoules (kJ).
New more economical water showers would add approximately 8l/min. If the user takes a shower once a day for 5 minutes, what would be the total amount of water consumed per year?
Suppose that the average U.S. household uses 10100 kWh10100 kWh (kilowatt‑hours) of energy in a year. If the average rate of energy consumed by the house was instead diverted to lift a 1.80×103 kg car 11.3 m into the air, how long would it take? 1. car: ______ seconds? Using the same rate of energy consumption, how long would it take to lift a loaded Boeing 747 airplane, with a mass of 4.10×105 kg, to a cruising altitude of 9.92 km? 2. airplane: ______ seconds?
8.36 grams of a mystery substance of food with a molar mass of 149.36 g/mol is burned in a bomb calorimeter. The water in the bomb calorimeter absorbs 105,961 Joules from the burning of the substance. Calculate the heat of combustion of the mystery substance in kJ/mol. (Please input your answer as a negative number.) (DO NOT PUT UNITS IN YOUR ANSWER.) Assume that all of the heat lost by the substance is transferred to the water and no heat is lost to the surroundings.
Estimate how many molecules of air are in each 2.5-L breath you inhale that were also in the last breath Galileo took. [Hint: Assume the atmosphere is about 10 km high and of constant density.] Express your answer using two significant figures. N=?? (I got 27, but I was also wrong).
World wind energy generating capacity, W, was 371 gigawatts by the end of 2014 and has been increasing at a continuous rate of approximately 16.8% per year. Assume this rate continues. (Generating capacity is the maximum amount of power generated per unit time.) (a) Give a formula for W, in gigawatts, as a function of time, t, in years since the end of 2014. W (t) = gigawatts %3D (b) When is wind capacity predicted to pass 500 gigawatts? Wind capacity will pass 500 gigawatts during the year
In Europe, nutritional information is given in kilojoules instead of nutritional calories. A packet of soup has the following nutritional information: 250 ml of soup = 235 kilojoules How would that same packet be labeled in the US if the information has to be given in nutritional calories per cup? (2 cups to 1 pint)
The recommended daily caloric intake is 2000 calories (8,400,000J). This is because this is the same value for how much the average body loses to heat and work in a typical day (your change in energy is zero because you take in the same amount of energy you lose). A) If you lose a total of 8,400,000J (Qout+W=total lost), but consume 1200 calories of food (5,000,000J), what would your change in energy be? B) Assuming your change in energy is negative (hint-it should be), where does your body get the extra energy to maintain it's temperature?
What does one month's heating cost in the home of a neighbor who uses a heat pump to provide the same amount of heating? Express your answer in dollars.
A study finds that the metabolic rate of mammals is proportional to m314, where m is the total body mass. By what factor does exceed that of a 6.11-kg cat?
In a patient, the biodose from a distance of 50 cm is 5 minutes, what will be the biodose from a distance of 200 cm?
Sarah drove her car a distance of 691.9 km, and used 41.7 L of gasoline (petrol). What is her fuel efficiency in miles per gallon Use the following facts: 1km=0.6214 mi 1 gal=3.8 L Round your answer to the nearest tenth