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# Work and Energy

In: Science

Submitted By ttksharp
Words 698
Pages 3
First discuss how energy can be converted from one form to another, giving specific examples.
All forms of energy can be converted to another form of. For example: “A pendulum is an object, called a bob, suspended by a string or wire for support. If the bob is moved to one side and then released, it will swing back and forth in an arc. At that moment the bob reaches the top of its swing, it stops for an instant, then begins another swing. At that instant of stopping, the bob has 100 percent potential energy and no kinetic energy. As the bob starts back down through the swing, it is gaining kinetic energy and losing potential energy. At the instant the bob is at the bottom of the swing, it has 100 percent kinetic energy and no potential energy. AS the bob climbs through the other half of the arc, it is gaining potential energy and losing kinetic energy until it again reaches an instantaneous stop at the top, and the process starts over. The kinetic energy of the bob at the bottom of the arc is equal to the potential energy it had at the top of the arc. Disregarding friction, the sum of potential energy and kinetic energy remains constant throughout the swing.” (Integrated Science, pg. 64)
Some other examples of how a form of energy converts into another are: a light bulb converts electrical energy into radiant energy. A car converts chemical energy into mechanical energy, and a solar cell converts radiant energy into electrical energy.
Define what we mean by fossil fuels and explain why they are an attractive source of energy.
Fossil fuels are organic fuels that contain the stored radiant energy of the Sun converted to chemical energy by plants or animals that lived millions of years ago; coal, petroleum, and natural gas are the common fossil fuels.
Describe two different energy alternatives to fossil fuels in detail. Discuss how they work, how they compare with fossil fuels, and their relative advantages and disadvantages.
Moving Water
Moving Water is considered to be a renewable energy source, unlimited as long as it rains. Moving water has been an energy source for thousands of years. Hydroelectric plants generate about 3 percent of the United States’ total energy consumption at about 2,400 power-generating damns across the nation. Hydropower furnished about 40 percent of the United States electric power in 1940. Today, dams furnished 9 percent of the electric power. Energy consumption has increased, but hydropower production has not kept pace because geography limits the number of sites that can be built. (Integrated Science, pg. 67)
Water from a reservoir is conducted through large pipes called penstocks to a powerhouse, where it is directed against turbine blades that turn a shaft on an electric generator. (Integrated Science, pg. 67)
Nuclear
Nuclear energy is the form of energy from reactions involving the nucleus, the innermost part of an atom. Nuclear power plants have been using nuclear energy to produce electricity for centuries. Energy is released as the nuclei of uranium and plutonium atoms split, or undergo fission. The fissioning takes place in a large steel vessel called a reactor. Water is pumped through the reactor to produce steam, which is used to produce electrical energy, just as in fossil fuel power plants. Nuclear power plants use nuclear energy to produce electricity, but there are opponents of this process. The electric utility companies view nuclear as one energy source used to produce electricity. Petroleum, coal, and hydropower are also presently utilized as energy sources for electric power productions. The electric companies are concerned that petroleum and natural gas are becoming increasingly expensive, and there are questions about long-term supplies. Hydropower has limited potential for growth, and solar energy is prohibitively expensive day. Utility companies see two major energy sources that are available for growth are coal and nuclear. There are advantages and disadvantages to each, however utility companies feel they must use coal and nuclear power until the new technologies, such as solar power are economically feasible. (Integrated Science, pg. 67)

References
Enger, Eldon D., Ross, Frederick C., Tillery, Bill W., (2009), Integrated Science

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