# Search results

1. ### Methane and CO2 atmospheric lifetime math problem

Homework Statement On a per-molecule basis, methane is 26 times more effective as an infrared absorber than is CO2. Calculate the corresponding ratio on a per-unit-mass basis, and compare it with the 20-year GWP for methane. What's the reason for any discrepncy you find? (CO2 atmospheric...
2. ### Climate Sensitivity math problem

Homework Statement Using a climate sensitivity of 0.5K per watt per square meter, estimate how much of the .9 c global temperature increase since 1900 could be due to solar forcing who value is the range of .06 to .24 w/m2 Homework Equations The Attempt at a Solution I am not...
3. ### Mars and Jupiter's atmosphere math question

Homework Statement What should be the temperature of a spherical asteroid located between Mars and Jupiter, twice as far from the Sun as Earth? The asteroid has no atmosphere and its albedo is .15. Homework Equations The Attempt at a Solution The asteroid is twice as far from...
4. ### Energy content of gasoline and hydrogen comparative math question

Homework Statement A typical car gas tank holds 15 gallons A) Calculate the energy content of this much gasoline B) Calculate the chemical energy content of 15 gallons of hydrogen gas under normal conditions (12.8 MJ/m^3) and compare with the energy content of gasoline Homework...
5. ### Waste power plant efficiency math problem

Homework Statement If 230 million tonnes of solid waste were burned in waste-to-energy power plants that are 20% efficient a) how many kilowatt- hours of electrical energy could be produced in a year? Compare this quantity with the total US electrical energy production of 3.8 trillion...
6. ### Bertz law math problem

Homework Statement The density of air under normal conditions is about 1.2 kg/m^3. For a wind speed of 10 m/s find a) the actual power carried by the wind b) the maximum possible power (Bert'z limit) extractable by a wind turbine with a blade area of 10 m^2 and c) the actual power...
7. ### Flow of a river power math question?

Homework Statement The average flow rate in the Niagara River is 6.0 x 10^6 kg/s and the water drops 50 m over Niagara falls. If all this energy could be harnessed to generate hydroelectric efficiency at 90% efficiency, what would be the electric power output? Homework Equations P=mgh...
8. ### PV power plant efficiency math problem?

Homework Statement The controversial Cheviot open-pit coal mine in Alberta, Canada occupies 7,455 hectares (one hectare= 10^4 m^2) and produces 1.4 million tonnes of coal per year. a) use the energy content of coal of 29 MJ/kg to find the power in watts corresponding to this rate of...
9. ### Power used to heat water and efficiency math problem

Homework Statement A household uses 100 gallons of hot water per day (1 gallon of water has a mass of 3.78 kg) and the water temperature must be raised from 10°C to 50°C a) find the average power needed to heat the water. b)Then assume you have solar collectors with 55% average...
10. ### Geothermal heat extraction math problem

Homework Statement The actual efficiency of a geothermal power plant using a 200 C geothermal resource is only about 7%. Take this value as typical of California's Geysers geothermal field, which produces 900 MW of electric power. a) Find the actual rate of geothermal heat extraction at...
11. ### Burning fossil fuels math problem

Homework Statement Humankind uses about 500 EJ of energy each year nearly all of it from fossil fuels. If the energy content of fossil fuels is 40 MJ/kg estimate the total mass of fossil fuels we burn each year. Homework Equations I am not sure if this is a relevant equation but in my...