Lesson 4.3: Efficiency
Completion requirements
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Lesson 4.3: Efficiency |
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What does efficiency mean to you? Does it mean a good use of your time? Energy efficiency describes how much energy is used to do a job compared to how much energy is wasted. Machines waste some input energy because of friction. What are some ways that you can reduce friction in a machine? View the following media clip "Reducing Friction".
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Read "Efficiency" on page 145 of your textbook. |
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Answer the following self-check questions. |
| Question 1. | What is meant by a machine's efficiency? | |
| Question 2. | Is there such a thing as a 100% efficient machine? | |
| Question 3. | How can friction between two solids be reduced? | |
| Question 4. | What is a lubricant? | |
| Question 5. | What is the lubricant in a car engine? | |
| Question 6. | What is the lubricant in a hovercraft? | |
| Question 7. | What is the effect of a lubricant on the efficiency of a machine? |
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