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Ethics and Sustainability Tutorial 1
1) Assume that a generation is approximately 25 years If each female has on average x children who survive into adulthood (half of whom are female) estimate how the population would change over time for different values of x Compare your calculations with the estimated historical size of the world population reported on the US Census website Given this comparison what do you think is the approximate historical value of x
Starting at 10000 BC the population of the world was assumed around 5000000 people with 2500000 women If each female has x children that survive then the number of female children = frac12 x
So for the 250000 women the number of female children = 1250000 x
Hence the total number of male children = 1250000 x
And the total number of children is = 2500000 x
This pattern can be continued
2500000 women (1st generation)
1250000 x female children (2nd generation)
625000 x2 female children (3rd generation)
312500 x3 female children (4th generation)
156240 x4 female children (5th generation)
Where one generation is 25 years If x = 1
1st generation 5000000
2nd generation 2500000
3rd generation 1250000
Ie The total population will decrease
If x = 2
1st generation 5000000
2nd generation 5000000
3rd generation 5000000
ie the total population will remain constant
If x = 3
1st generation 5000000
2nd generation 7500000
3rd generation 11250000
ie the total population will gradually increase
If x = 4
1st generation 5000000
2nd generation 10000000
3rd generation 20000000
ie the total population will double between generations
1
1 University of Strathclyde cp305 ethics and sustainability course notes
From this graph of total world population against time it can be seen that the population remained constant between 10000 BC and 2000 BC Therefore the value of x = 2
In recent years the population has increased dramatically The value of x = 4 This is due to the industrial revolution which has contributed to improved living standards and healthcare Children are much more likely to survive into adulthood
2 (a) Given a solar constant of S = 1368Wm10485762 estimate the maximum flux of energy from the Sun in Glasgow (latitude 55_500
N) on June 22 and December 22
On June 22nd
Flux = S x cos Θ = 1368 Wm2 x cos 315deg = 116641 Wm2
On December 22nd
Flux = S x cos Θ = 1368 Wm2 x cos 785deg = 27274 Wm2
(b) The current rate of energy consumption in the world is estimated to be 12 _ 109 toe where 1 toe = 41868 _ 109 J Estimate the surface area required to supply the energy consumption of the world using photovoltaic cells with a conversion efficiency of 10 List any other assumptions made
World energy consumption
It was assumed that the value provided was the energy consumption for one year
12 x 10 9 toeyear = 5024 x 1020 Jyear = 159 x 1013 Js
Available energy
1368 Wm2 x 01 = 1368 Wm2
Total required surface area
159times1013 J s1368W m2
=116times1011m2
(c) What are the practical problems associated with replacing the use of fossil fuels with solar energy
The variability of the sunrsquos energy presents problems At certain times less energy will be produced potentially causing a shortage of energy
This would need to be prevented by using back up sources of energy ie nuclear coalAt present the electricity grid isnrsquot capable of storing excess energy produced by the photovoltaic cells New energy storage systems must also be developed
3 Given that the solar constant of the Earth is S = 1368Wm10485762 determine the solar constant of Venus and the temperatures of the Earth and Venus The Stefan-Boltzmann constant is _ = 5670373 _ 1010485768Wm10485762 K10485764 Use the data provided in the table below
S=S0times(r0r)2
Where S = solar flux received at planetS0 = solar flux at earthR = distance of planet from the sunR0 = distance of earth from the sun
For venus
S=S0times(r0r)2
=1368times( 149598times109
108209times109)2
=2615W m2
Temperature of the earth
Power absorbed by the planet
Pincident=Sπr2=1368timesπtimes31855002=436times1016W
Taking into account the albedo
P= (1minusα )Pincident=(1minus0306 )times(436times1016)=303times1016
Power radiated by the planet
Pblackbody=4 π r2σT 4
Taking into account dissipation
P=ε Pblackbody
So Pblackbody = 303 X 10160612 = 495 X 1016 W
T 4=495times1016
4 π r2σ T 4=2876K
Temperature of venus
Power absorbed by the planet
Pincident=Sπr2=2615timesπtimes30259002=7 52times1016W
Taking into account the albedo
P= (1minusα )Pincident=(1minus07 )times(7 52times1016)=226times1016
Power radiated by the planet
Pblackbody=4 π r2σT 4
Taking into account dissipation
P=ε Pblackbody
So Pblackbody = 226 X 1016001 = 226 X 1018 W
T 4=226times1018
4 π r2σ T 4=7672K
4 Potential of wind power Assuming that the half of the Earth that is illuminated by the Sun is at a temperature TH and the dark half of the Earth is at a temperature TC estimate the amount of
power (useful work) that can be generated from this temperature difference as a function of TH What is the maximum power (useful work) that can be generated and what percentage is this of the total solar energy that falls on the Earth This is an estimate for the potential work that can be extracted from wind power Recall that the efficiency _ of a Carnot (reversible) engine operating between temperatures TH and TC is _ = 1 1048576 TC=TH Take the solar constant to be S = 1368Wm10485762 and the background temperature of space to be 0 K
5 Within the Malthusian economic model explain the impact on the population and average percapita income y of (i) the declaration of a war which then becomes ongoing (ii) an increase intaxes and (iii) the development of a new technology that makes food production more efficient Be sure to include diagrams of the birth rate death rate and total population with per capitaincome in your discussion
(i)
2
2 httpeconlogeconliborgarchivesclark2jpg
A war will reduce the population of a country for a period of time while the war is ongoing The Malthusian model predicts that this decrease in population will lead to an increase in the wage of an average person (graph 2) Once the population has recovered the wage will begin to decrease
(ii) An increase in taxes will mean a decrease in the average personrsquos wage Correspondingly the death rate will increase
(iii) This improvement will cause a decrease in death rate Correspondingly the population will increase and the average wage will fall
Ie The total population will decrease
If x = 2
1st generation 5000000
2nd generation 5000000
3rd generation 5000000
ie the total population will remain constant
If x = 3
1st generation 5000000
2nd generation 7500000
3rd generation 11250000
ie the total population will gradually increase
If x = 4
1st generation 5000000
2nd generation 10000000
3rd generation 20000000
ie the total population will double between generations
1
1 University of Strathclyde cp305 ethics and sustainability course notes
From this graph of total world population against time it can be seen that the population remained constant between 10000 BC and 2000 BC Therefore the value of x = 2
In recent years the population has increased dramatically The value of x = 4 This is due to the industrial revolution which has contributed to improved living standards and healthcare Children are much more likely to survive into adulthood
2 (a) Given a solar constant of S = 1368Wm10485762 estimate the maximum flux of energy from the Sun in Glasgow (latitude 55_500
N) on June 22 and December 22
On June 22nd
Flux = S x cos Θ = 1368 Wm2 x cos 315deg = 116641 Wm2
On December 22nd
Flux = S x cos Θ = 1368 Wm2 x cos 785deg = 27274 Wm2
(b) The current rate of energy consumption in the world is estimated to be 12 _ 109 toe where 1 toe = 41868 _ 109 J Estimate the surface area required to supply the energy consumption of the world using photovoltaic cells with a conversion efficiency of 10 List any other assumptions made
World energy consumption
It was assumed that the value provided was the energy consumption for one year
12 x 10 9 toeyear = 5024 x 1020 Jyear = 159 x 1013 Js
Available energy
1368 Wm2 x 01 = 1368 Wm2
Total required surface area
159times1013 J s1368W m2
=116times1011m2
(c) What are the practical problems associated with replacing the use of fossil fuels with solar energy
The variability of the sunrsquos energy presents problems At certain times less energy will be produced potentially causing a shortage of energy
This would need to be prevented by using back up sources of energy ie nuclear coalAt present the electricity grid isnrsquot capable of storing excess energy produced by the photovoltaic cells New energy storage systems must also be developed
3 Given that the solar constant of the Earth is S = 1368Wm10485762 determine the solar constant of Venus and the temperatures of the Earth and Venus The Stefan-Boltzmann constant is _ = 5670373 _ 1010485768Wm10485762 K10485764 Use the data provided in the table below
S=S0times(r0r)2
Where S = solar flux received at planetS0 = solar flux at earthR = distance of planet from the sunR0 = distance of earth from the sun
For venus
S=S0times(r0r)2
=1368times( 149598times109
108209times109)2
=2615W m2
Temperature of the earth
Power absorbed by the planet
Pincident=Sπr2=1368timesπtimes31855002=436times1016W
Taking into account the albedo
P= (1minusα )Pincident=(1minus0306 )times(436times1016)=303times1016
Power radiated by the planet
Pblackbody=4 π r2σT 4
Taking into account dissipation
P=ε Pblackbody
So Pblackbody = 303 X 10160612 = 495 X 1016 W
T 4=495times1016
4 π r2σ T 4=2876K
Temperature of venus
Power absorbed by the planet
Pincident=Sπr2=2615timesπtimes30259002=7 52times1016W
Taking into account the albedo
P= (1minusα )Pincident=(1minus07 )times(7 52times1016)=226times1016
Power radiated by the planet
Pblackbody=4 π r2σT 4
Taking into account dissipation
P=ε Pblackbody
So Pblackbody = 226 X 1016001 = 226 X 1018 W
T 4=226times1018
4 π r2σ T 4=7672K
4 Potential of wind power Assuming that the half of the Earth that is illuminated by the Sun is at a temperature TH and the dark half of the Earth is at a temperature TC estimate the amount of
power (useful work) that can be generated from this temperature difference as a function of TH What is the maximum power (useful work) that can be generated and what percentage is this of the total solar energy that falls on the Earth This is an estimate for the potential work that can be extracted from wind power Recall that the efficiency _ of a Carnot (reversible) engine operating between temperatures TH and TC is _ = 1 1048576 TC=TH Take the solar constant to be S = 1368Wm10485762 and the background temperature of space to be 0 K
5 Within the Malthusian economic model explain the impact on the population and average percapita income y of (i) the declaration of a war which then becomes ongoing (ii) an increase intaxes and (iii) the development of a new technology that makes food production more efficient Be sure to include diagrams of the birth rate death rate and total population with per capitaincome in your discussion
(i)
2
2 httpeconlogeconliborgarchivesclark2jpg
A war will reduce the population of a country for a period of time while the war is ongoing The Malthusian model predicts that this decrease in population will lead to an increase in the wage of an average person (graph 2) Once the population has recovered the wage will begin to decrease
(ii) An increase in taxes will mean a decrease in the average personrsquos wage Correspondingly the death rate will increase
(iii) This improvement will cause a decrease in death rate Correspondingly the population will increase and the average wage will fall
From this graph of total world population against time it can be seen that the population remained constant between 10000 BC and 2000 BC Therefore the value of x = 2
In recent years the population has increased dramatically The value of x = 4 This is due to the industrial revolution which has contributed to improved living standards and healthcare Children are much more likely to survive into adulthood
2 (a) Given a solar constant of S = 1368Wm10485762 estimate the maximum flux of energy from the Sun in Glasgow (latitude 55_500
N) on June 22 and December 22
On June 22nd
Flux = S x cos Θ = 1368 Wm2 x cos 315deg = 116641 Wm2
On December 22nd
Flux = S x cos Θ = 1368 Wm2 x cos 785deg = 27274 Wm2
(b) The current rate of energy consumption in the world is estimated to be 12 _ 109 toe where 1 toe = 41868 _ 109 J Estimate the surface area required to supply the energy consumption of the world using photovoltaic cells with a conversion efficiency of 10 List any other assumptions made
World energy consumption
It was assumed that the value provided was the energy consumption for one year
12 x 10 9 toeyear = 5024 x 1020 Jyear = 159 x 1013 Js
Available energy
1368 Wm2 x 01 = 1368 Wm2
Total required surface area
159times1013 J s1368W m2
=116times1011m2
(c) What are the practical problems associated with replacing the use of fossil fuels with solar energy
The variability of the sunrsquos energy presents problems At certain times less energy will be produced potentially causing a shortage of energy
This would need to be prevented by using back up sources of energy ie nuclear coalAt present the electricity grid isnrsquot capable of storing excess energy produced by the photovoltaic cells New energy storage systems must also be developed
3 Given that the solar constant of the Earth is S = 1368Wm10485762 determine the solar constant of Venus and the temperatures of the Earth and Venus The Stefan-Boltzmann constant is _ = 5670373 _ 1010485768Wm10485762 K10485764 Use the data provided in the table below
S=S0times(r0r)2
Where S = solar flux received at planetS0 = solar flux at earthR = distance of planet from the sunR0 = distance of earth from the sun
For venus
S=S0times(r0r)2
=1368times( 149598times109
108209times109)2
=2615W m2
Temperature of the earth
Power absorbed by the planet
Pincident=Sπr2=1368timesπtimes31855002=436times1016W
Taking into account the albedo
P= (1minusα )Pincident=(1minus0306 )times(436times1016)=303times1016
Power radiated by the planet
Pblackbody=4 π r2σT 4
Taking into account dissipation
P=ε Pblackbody
So Pblackbody = 303 X 10160612 = 495 X 1016 W
T 4=495times1016
4 π r2σ T 4=2876K
Temperature of venus
Power absorbed by the planet
Pincident=Sπr2=2615timesπtimes30259002=7 52times1016W
Taking into account the albedo
P= (1minusα )Pincident=(1minus07 )times(7 52times1016)=226times1016
Power radiated by the planet
Pblackbody=4 π r2σT 4
Taking into account dissipation
P=ε Pblackbody
So Pblackbody = 226 X 1016001 = 226 X 1018 W
T 4=226times1018
4 π r2σ T 4=7672K
4 Potential of wind power Assuming that the half of the Earth that is illuminated by the Sun is at a temperature TH and the dark half of the Earth is at a temperature TC estimate the amount of
power (useful work) that can be generated from this temperature difference as a function of TH What is the maximum power (useful work) that can be generated and what percentage is this of the total solar energy that falls on the Earth This is an estimate for the potential work that can be extracted from wind power Recall that the efficiency _ of a Carnot (reversible) engine operating between temperatures TH and TC is _ = 1 1048576 TC=TH Take the solar constant to be S = 1368Wm10485762 and the background temperature of space to be 0 K
5 Within the Malthusian economic model explain the impact on the population and average percapita income y of (i) the declaration of a war which then becomes ongoing (ii) an increase intaxes and (iii) the development of a new technology that makes food production more efficient Be sure to include diagrams of the birth rate death rate and total population with per capitaincome in your discussion
(i)
2
2 httpeconlogeconliborgarchivesclark2jpg
A war will reduce the population of a country for a period of time while the war is ongoing The Malthusian model predicts that this decrease in population will lead to an increase in the wage of an average person (graph 2) Once the population has recovered the wage will begin to decrease
(ii) An increase in taxes will mean a decrease in the average personrsquos wage Correspondingly the death rate will increase
(iii) This improvement will cause a decrease in death rate Correspondingly the population will increase and the average wage will fall
This would need to be prevented by using back up sources of energy ie nuclear coalAt present the electricity grid isnrsquot capable of storing excess energy produced by the photovoltaic cells New energy storage systems must also be developed
3 Given that the solar constant of the Earth is S = 1368Wm10485762 determine the solar constant of Venus and the temperatures of the Earth and Venus The Stefan-Boltzmann constant is _ = 5670373 _ 1010485768Wm10485762 K10485764 Use the data provided in the table below
S=S0times(r0r)2
Where S = solar flux received at planetS0 = solar flux at earthR = distance of planet from the sunR0 = distance of earth from the sun
For venus
S=S0times(r0r)2
=1368times( 149598times109
108209times109)2
=2615W m2
Temperature of the earth
Power absorbed by the planet
Pincident=Sπr2=1368timesπtimes31855002=436times1016W
Taking into account the albedo
P= (1minusα )Pincident=(1minus0306 )times(436times1016)=303times1016
Power radiated by the planet
Pblackbody=4 π r2σT 4
Taking into account dissipation
P=ε Pblackbody
So Pblackbody = 303 X 10160612 = 495 X 1016 W
T 4=495times1016
4 π r2σ T 4=2876K
Temperature of venus
Power absorbed by the planet
Pincident=Sπr2=2615timesπtimes30259002=7 52times1016W
Taking into account the albedo
P= (1minusα )Pincident=(1minus07 )times(7 52times1016)=226times1016
Power radiated by the planet
Pblackbody=4 π r2σT 4
Taking into account dissipation
P=ε Pblackbody
So Pblackbody = 226 X 1016001 = 226 X 1018 W
T 4=226times1018
4 π r2σ T 4=7672K
4 Potential of wind power Assuming that the half of the Earth that is illuminated by the Sun is at a temperature TH and the dark half of the Earth is at a temperature TC estimate the amount of
power (useful work) that can be generated from this temperature difference as a function of TH What is the maximum power (useful work) that can be generated and what percentage is this of the total solar energy that falls on the Earth This is an estimate for the potential work that can be extracted from wind power Recall that the efficiency _ of a Carnot (reversible) engine operating between temperatures TH and TC is _ = 1 1048576 TC=TH Take the solar constant to be S = 1368Wm10485762 and the background temperature of space to be 0 K
5 Within the Malthusian economic model explain the impact on the population and average percapita income y of (i) the declaration of a war which then becomes ongoing (ii) an increase intaxes and (iii) the development of a new technology that makes food production more efficient Be sure to include diagrams of the birth rate death rate and total population with per capitaincome in your discussion
(i)
2
2 httpeconlogeconliborgarchivesclark2jpg
A war will reduce the population of a country for a period of time while the war is ongoing The Malthusian model predicts that this decrease in population will lead to an increase in the wage of an average person (graph 2) Once the population has recovered the wage will begin to decrease
(ii) An increase in taxes will mean a decrease in the average personrsquos wage Correspondingly the death rate will increase
(iii) This improvement will cause a decrease in death rate Correspondingly the population will increase and the average wage will fall
Taking into account dissipation
P=ε Pblackbody
So Pblackbody = 303 X 10160612 = 495 X 1016 W
T 4=495times1016
4 π r2σ T 4=2876K
Temperature of venus
Power absorbed by the planet
Pincident=Sπr2=2615timesπtimes30259002=7 52times1016W
Taking into account the albedo
P= (1minusα )Pincident=(1minus07 )times(7 52times1016)=226times1016
Power radiated by the planet
Pblackbody=4 π r2σT 4
Taking into account dissipation
P=ε Pblackbody
So Pblackbody = 226 X 1016001 = 226 X 1018 W
T 4=226times1018
4 π r2σ T 4=7672K
4 Potential of wind power Assuming that the half of the Earth that is illuminated by the Sun is at a temperature TH and the dark half of the Earth is at a temperature TC estimate the amount of
power (useful work) that can be generated from this temperature difference as a function of TH What is the maximum power (useful work) that can be generated and what percentage is this of the total solar energy that falls on the Earth This is an estimate for the potential work that can be extracted from wind power Recall that the efficiency _ of a Carnot (reversible) engine operating between temperatures TH and TC is _ = 1 1048576 TC=TH Take the solar constant to be S = 1368Wm10485762 and the background temperature of space to be 0 K
5 Within the Malthusian economic model explain the impact on the population and average percapita income y of (i) the declaration of a war which then becomes ongoing (ii) an increase intaxes and (iii) the development of a new technology that makes food production more efficient Be sure to include diagrams of the birth rate death rate and total population with per capitaincome in your discussion
(i)
2
2 httpeconlogeconliborgarchivesclark2jpg
A war will reduce the population of a country for a period of time while the war is ongoing The Malthusian model predicts that this decrease in population will lead to an increase in the wage of an average person (graph 2) Once the population has recovered the wage will begin to decrease
(ii) An increase in taxes will mean a decrease in the average personrsquos wage Correspondingly the death rate will increase
(iii) This improvement will cause a decrease in death rate Correspondingly the population will increase and the average wage will fall
power (useful work) that can be generated from this temperature difference as a function of TH What is the maximum power (useful work) that can be generated and what percentage is this of the total solar energy that falls on the Earth This is an estimate for the potential work that can be extracted from wind power Recall that the efficiency _ of a Carnot (reversible) engine operating between temperatures TH and TC is _ = 1 1048576 TC=TH Take the solar constant to be S = 1368Wm10485762 and the background temperature of space to be 0 K
5 Within the Malthusian economic model explain the impact on the population and average percapita income y of (i) the declaration of a war which then becomes ongoing (ii) an increase intaxes and (iii) the development of a new technology that makes food production more efficient Be sure to include diagrams of the birth rate death rate and total population with per capitaincome in your discussion
(i)
2
2 httpeconlogeconliborgarchivesclark2jpg
A war will reduce the population of a country for a period of time while the war is ongoing The Malthusian model predicts that this decrease in population will lead to an increase in the wage of an average person (graph 2) Once the population has recovered the wage will begin to decrease
(ii) An increase in taxes will mean a decrease in the average personrsquos wage Correspondingly the death rate will increase
(iii) This improvement will cause a decrease in death rate Correspondingly the population will increase and the average wage will fall
A war will reduce the population of a country for a period of time while the war is ongoing The Malthusian model predicts that this decrease in population will lead to an increase in the wage of an average person (graph 2) Once the population has recovered the wage will begin to decrease
(ii) An increase in taxes will mean a decrease in the average personrsquos wage Correspondingly the death rate will increase
(iii) This improvement will cause a decrease in death rate Correspondingly the population will increase and the average wage will fall
