This lesson contains 16 slides, with text slides and 1 video.
Items in this lesson
This lesson
Recap Conservation of energy
Checking the homework
Efficiency and sankey diagrams
Working independently
Slide 1 - Slide
Goals
Answering the learning goals of previous lesson
To name the formula for effiency
Applying the formula for effiency
Reading a sankey diagram
Slide 2 - Slide
Recap conservation of energy
1. State the law of conservation of energy
2. What is always true about the total amount of energy generated compared to the amount of energy used?
3. What does it mean to say that energy is useful?
What does it mean to say that energy is wasted?
4. What two factors in an energy transfer are compared together to detimerine the efficiency? And how?
Slide 3 - Slide
Goals
1. State the law of conservation of energy
2. What is always true about the total amount of energy generated compared to the amount of energy used?
3. What does it mean to say that energy is useful?
What does it mean to say that energy is wasted?
4. What two factors in an energy transfer are compared together to detimerine the efficiency? And how?
Slide 4 - Slide
Checking the homework
Exercises §2.5
Slide 5 - Slide
Efficiency and
sankey diagrams
Slide 6 - Slide
Slide 7 - Video
What is the formula for efficiency?
Slide 8 - Slide
Slide 9 - Slide
Slide 10 - Slide
1) A construction worker puts 20 J of energy in to one strike of his hammer on the head of a nail. The energy transferred to driving the nail in to the wood is 8.0 J. What is the efficiency of the construction worker's hammering?
2) A particular chemical process has an energy efficiency of only 3.00%. To complete this large-scale chemical process, 140,000 J of energy is input. What is the energy output of this process?
