Analyzing Energy Graphs – Answer all questions in Complete Sentences
Roller Coaster Energy Data 450 Total Gravitational Energy at Top of First Hill 400 Energy Data at Bottom Taken at Bottom of First Hill 350 300 250 200 Joules) 150 100
Energy (Thousands Energy of 50 0 Kinetic Energy at Thermal Energy Sound Energy Gravitational Potential Bottom of Hill Energy at Top of Hill
Above is a graph of Energy data taken from a Roller Coaster at King’s Dominion Theme Park in Virginia. Analyze the data and assess its validity. Record your conclusions below:
The above data shows that the roller coaster car has a total of 425 thousand Joules of gravitational potential energy at the top of the hill. Since the car is not moving at the top of the hill its kinetic energy is 0J. Thus, the total energy of the roller coaster car is 425,000J (425,000J + 0J) at the top of the hill. As the roller coaster car goes down the hill the 425,000J of gravitational potential energy is converted to moving kinetic energy (400,000J), thermal kinetic energy (75,000J) caused from the friction of the wheels rubbing against the rails and sound kinetic energy (25,000J) for a total of 500,000J. This is a violation of the Law of Conservation of Energy because 500,000J of output energy came from 425,000J of input energy.
1000 Coal Fired Power Plant Energy Data 800 Total Chemical Energy of Coal into Plant Energy outputs of Power Plant 600 400 200 0 Electrical Energy Radiant Energy Thermal Energy Sound Energy Total Chemical Potential Energy
Energy (Millions of Joules) Input
Above is a graph of Energy data taken from the Point Huron Power Plant. Discuss the class and type of input energy for this type of power plant. Briefly describe what a power plant does. Analyze the data and assess its validity. Record your conclusions below:
The role of a power plant is to take in one form of energy and transform this energy into a different form of energy that can be easily used by humans. The output energy of a power plant is typically in the form of electrical kinetic energy. The main goal of the Point Huron Power Plant is to take in chemical potential energy in the form of coal and transform this into electrical kinetic energy. In the process of this energy conversion radiant, thermal and sound energy are also produced. From the above data it can be seen that the Point Huron Plant takes in 925,000,000Joules of chemical potential energy and transforms this into 575,000,000J of Electrical Energy, 50,000,000J of Radiant energy, 250,000,000J of Thermal energy and 50,000,000J of Sound energy for a total output of 925,000,000J (575+50+250+50). This data is valid because the amount of energy that plant takes in equals the amount of energy that the power plant puts out. In other words, no energy was created or destroyed which is in accordance with the Law of Conservation of Energy. Computer 5% ClothesWasher Other HouseHold Energy Usage 4% 3% Refrigerator TV Cable 20% 7%
Freezer 16% Dishwasher 4% Heating/AC Lights 31% 10%
Above is a graph of Household Energy Usage taken from the Department of Energy’s 2010 Report. Name and then discuss the class and types of input energy to a typical home (not shown on this graph). Where is most of the energy used in a typical US home?
Today, most homes energy enters the home as electrical kinetic energy and chemical potential energy. The electrical kinetic energy enters the home on wires which are typically buried but can be seen above ground in older homes. The chemical potential energy is usually either in the form of natural gas and in some cases oil or propane (big tanks on the side of some homes). As seen in the graph above, most of a households energy usage (51%) goes to running the refrigerator and heating or air conditioning the home. If you add the freezer (16%) it can be seen that heating or cooling of the air inside the house consumes two-thirds or 67% of a homes total energy usage! The remaining 33% is used by a variety of household items such as lights, dishwasher, tv etc.
Above is a graph of Household Energy Usage data taken from the DOEs 2010 Report. Answer the following questions: A) How much of our energy comes from Fossil Fuels? B) What class and type of energy does a Fossil Fuel contain? How do you know? C) What percent of the US’s energy comes from Hydropower? The above data shows the sources of the energy used in homes in the United States. From this data it can be seen that 83% (21+37+25) of energy comes from fossil fuels. Fossil fuels provide chemical potential energy and this is evident because a chemical change must occur (combustion chemical reaction) for the energy in the fossil fuel to be released. The remainder of a homes energy usage comes from Nuclear Power and Renewable Energy sources. Renewable energy sources make up 8% of a homes energy usage and of this 8%, hydropower makes up 31%. This means that only 2.4% (31% of 8%, or .31*.08) of a homes energy comes from hydroelectric power.