LA 75 kg person cannot go out for a long time due to Covid-19 restrictions. That's why he rides a bike at home to keep his weight stable. During bicycling, his body produces energy at a rate of about 450 W due to metabolism, 80% of which is converted to heat. The person's body gets rid of all this heat by evaporating water (sweat). How many grams of water must the person's body evaporate in an hour? The heat of vaporization of water at body temperature is 2.42 x 10^6 J/kg.

LA 75 kg person cannot go out for a long time due to Covid-19 restrictions. That's why he rides a bike at home to keep his weight stable. During bicycling, his body produces energy at a rate of about 450 W due to metabolism, 80% of which is converted to heat. The person's body gets rid of all this heat by evaporating water (sweat). How many grams of water must the person's body evaporate in an hour? The heat of vaporization of water at body temperature is 2.42 x 10^6 J/kg.

University Physics Volume 2

18th Edition

ISBN:9781938168161

Author:OpenStax

Publisher:OpenStax

Chapter1: Temperature And Heat

Section: Chapter Questions

Problem 101P: Many decisions are made on the basis of the payback period: the time it will take through savings to...

See similar textbooks

Similar questions

By counting squares in the following figure, estimate the fraction of argon atoms at T = 300 K that have speeds between 600 m/s and 800 m/s. The curve is correctly normalized. The value of a square is its length as measured on the x-axis times its height as measured on the y-axis, with the units given on those axes. `
A 0.250-kg aluminum bowl holding 0.800 kg of soup at 25.0 is placed in a freezer. What is the final temperature if 388 kJ of energy is transferred from the bowl and soup, assuming the soup's thermal properties are the same as that of water?
Many decisions are made on the basis of the payback period: the time it will take through savings to equal the capital cost of an investment. Acceptable payback times depend upon the business or philosophy one has. For some industries, a payback period is as small as 2 yeas) Suppose you wish to install the extra insulation in the preceding problem. If energy cost $1.00 per million joules and the insulation was $4.00 per square meter, then calculate the simple payback time. Take the average T for the 120-day heating season to be 15.0 .
One of a dilute diatomic gas occupying a volume of 10.00 L expands against a constant pressure of 2.000 atm when it is slowly heated. If the temperature of the gas rises by 10.00 K and 400.0 J of heat are added in the process, what is its final volume?
Suppose that a 59 kg boy and a 48 kg girl rode a car. They a traveled a 9 km distance. In 5.4 s, their speedometer changed from 30 to 60 kph. After their trip, they consumed 3 L of fuel. What is the efficiency of the car if it has a mass of 3760 kg, density of fuel = 719.7 kg/m3, heat of combustion of fuel = 37.21 MJ/kg.
A PHYS 1510 student was working on a robotics project. The joints on the machine they were building were powered by pistons. Based on how hot the machine was getting, the student was able to figure out that 2.34 J of thermal energy was produced by every piston every time the piston was fully extended to 0.4064 m. What was the force of friction that the piston experienced during every extension? Assume friction is the only source of thermal energy. Include units in Sl.
After the lockdown due to Covid-19, Ezekiel a 10year-old kid of mass 40kg starts to have an outdoor exercise for an hour by jogging around his place. He expends 200W of power during his jogging. If only 15% of the energy is used by the muscle and the rest of the energy is excreted by the body by sweating, determine the mass in kilograms, of his body fluid (water) lost. Round-off your answer to the nearest thousandths. Do not type the unit of your final answer. * L, = 2.26x106
mmh One ounce of a well-known breakfast cereal contains 110 Calories (1 food Calorie = 4186 J). If 2.0% of this energy could be converted by a weight lifter's body into work done in lifting a barbell, *53. what is the heaviest barbell that could be lifted a distance of 2.1 m?
An asteroid made out of iron (7860 kg/m3) strikes the Earth in an areawhere the oceans are very deep. The velocity of the asteroid upon impact isthe same for most debris hitting the Earth’s atmosphere, 30 km/s.The difference in potential energy from orbit to ground is negligible at thisspeed. Assuming that 80% of the asteroid’s kinetic energy is transferred toheating the water, what volume of water (assuming a density of 1000 kg/m3)will be vaporized? We will assume that the water is taken from 70o F tothe point that it becomes steam. Also, assume that the asteriod is spherical,with a radius of 750 m.
That same 0.005 kg is dropped off of the top of the Empire State building, which is about 443 meters tall. It hits the ground only going 5.28 m/s. How much energy, in J, was converted to heat as it fell? Round to two significant figures.
A 220 J of energy is required to raise the temperature of the temperature of aluminum from 15°C to 35°C. Calculate the mass of aluminum in kilograms. (specific heat of ahuminum = 900 J/kg-Co)
You use a quantity of fuel with a total energy content of 19.02 MJ to power an engine. If the average output of the engine over 2 hours was 2.12 kW, what is the efficiency of the engine?