Example: A 20 kg mass falls 30 m from a ledge where it was at rest. What is its kinetic energyjust before it hits the ground? How fast is the 20 kg mass from the problem before going, just before it hits the ground? A certain 1 GWe power plant produces electricity with an efficiency of 45%. What is the rate that the waste heat is discharged? What is its power rating in GWth ? The plant discharges the heat by taking in water from a river at 20 C and heating it to 40 C. At what rate does the plant need to take in water from the river to do this? 14 tonnes/s Need the specific heat of water = 4,184 J/kgC A 50 kg block of ice at -5C is heated by a 1 kW heat source for 20 minutes. How much of it melts? How long does it take the Greenland ice shelfto melt? V = 30 x 106 km3 A = 1.7 x 106 km2 Density of ice p = 920 kg/m3 What to choose for power? Insolation (radiation from the sun) is 340 W/m2 But there is also convection taking heat away Conduction (ground heat seeping upward) And latent heat of vaporization (precipitation) How the Earth and its atmosphere has changed over 4.6 billion years * How do we measure T in ancient times? stable isotope ratios etc in ice and sediment cores. * What cases the Temperature to change? Milankovich cycles, llyr solar cycle, ice albedo rock weathering, fast and slow carbon cycle, feedback mechanisms * What causes ice ages? What is the Paleocene-Eocene Thermal Maximum PETM ? Energy flow and detailed balance Be able to interpret energy diagram (next slides) Key terms: lnsolation, Reradiation at a different wavelength, Albedo, atmospheric absorption How do we model the climate and predict future temperatures, sea level rise, and ice melt? How do we validate climate models? CMIP: historical data and intercomparison Have general knowledge about the IPCC and the assessment reports ** Be able to define an RCP and read a graph with RCP2.6 and RCP8.5 Why are we are improving in energy efficiency what is energy intensity