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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
Homework Statement
The average temperature in Connecticut in January is 25.1 F. An average home uses 200 gallons of oil. The surface area is 2600 square feet. Assuming that all the energy content of your heating fuel escaped through the house walls and roof, estimate the average R value for...
Energy math question -- Energy to melt lake ice sheet
Homework Statement
Lake Champlain bordered by New York, Vermont and Quebec has a surface area of 1, 126 km^2. If it freezes solid in the winter with an average ice thickness of .5 m, how much total energy does it take ti melt the ice...
Homework Statement
The filament of typical light bulb is at a temperature of about 3,000 K. For a 100 W bulb, what is the surface area of the filament. You can assume that the entire 100 W goes into heating the filament and the filament has an emissivity of 1.
Homework Equations
The...