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Energy District Assessment Review
1. Why do many metal cooking utensils have wooden handles? 2. Describe the energy conversions that take place in a pendulum, and explain how energy is conserved (not lost or disappeared)? 3. Describe the energy conversions that take place in a roller coaster? 4. What type of energy conversion is used in a hair dryer? Wood in not a good conductor of heat. It is an insulator. As the pendulum swings downward, PE converts to KE. Some of the energy is converted into TE because of friction. As the roller coaster rolls down the track, PE is converted into KE. Some of the energy is converted into TE because of friction. Some of the energy is converted into sound energy. Electrical energy to light energy to sound energy to thermal energy.
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Energy District Assessment Review
5. You drop a ball and it bounces. Which ball will be the highest- the first or the last and why? 6. A girl has a ball that has a mass of 50 kg. She bounces the ball on the floor which had a speed of 5 m/s. What is the kinetic energy of the ball? (Hint: Use the kinetic energy formula K = mv2/2) The first bounce would be the highest because it would have the most energy. After the first bounce, energy is transferred into thermal energy and sound energy. K = mv2/ K = (50 x (5)2/ 2 K = 50 x 25/2 K = 1250/2 K = 625 J
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Energy District Assessment Review
7. Describe how fossil fuels can be converted into electrical energy. (Hint: Look at the diagram below) 8. What happens to the energy during the process in the diagram above? In other words, is the energy created, destroyed, lost or converted? Explain. 9. Two cups have the same temperature of 20 degrees Celsius. Cup A has 120 g of water in it, while cup B only has 45 g of water in it. Which cup will have more thermal energy? Why? 10. Name two disadvantages of using nonrenewable energy resources. Fossil fuels are burned to heat water in a pipe. The water in the pipe heats and becomes steam. The steam turns turbines which turn generators to produce electrical energy. Energy gets converted. The Law of Conservation of Energy states that energy can be neither created or destroyed, it just changes form or gets converted. Cup A because it has more water. More water will have more thermal energy. Can cause pollution, smog, acid rain. Not renewable.
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