Energy Ch 11 Presentation
11 Using Energy
© 2010 Pearson Education, Inc.
Slide 1
© 2010 Pearson Education, Inc.
Slide 2
© 2010 Pearson Education, Inc.
Slide 3
© 2010 Pearson Education, Inc.
Slide 4
Reading Quiz
1. A machine uses 1000 J of electric energy to raise a heavy mass, increasing its potential energy by 300 J. What is the efficiency of this process? A. B. C. D. E. 100% 85% 70% 35% 30%
© 2010 Pearson Education, Inc.
Slide 5
Reading Quiz
2. When the temperature of an ideal gas is increased, which of the following also increases? (1) The thermal energy of the gas; (2) the average kinetic energy of the gas; (3) the average potential energy of the gas; (4) the mass of the gas atoms; (5) the number of gas atoms.
A. B. C. D. E.
1, 2, and 3 1 and 2 4 and 5 2 and 3 All of 1–5
© 2010 Pearson Education, Inc.
Slide 6
Reading Quiz
3. A refrigerator is an example of a A. B. C. D. E. reversible process. heat pump. cold reservoir. heat engine. hot reservoir.
© 2010 Pearson Education, Inc.
Slide 7
Example Problem
Light bulbs are rated by the power that they consume, not the light that they emit. A 100 W incandescent bulb emits approximately 4 W of visible light. What is the efficiency of the bulb?
© 2010 Pearson Education, Inc.
Slide 8
Efficiency
© 2010 Pearson Education, Inc.
Slide 9
Example Problems
A person lifts a 20 kg box from the ground to a height of 1.0 m. A metabolic measurement shows that in doing this work her body uses 780 J of energy. What is her efficiency?
A 75 kg person climbs the 248 steps to the top of the Cape Hatteras lighthouse, a total climb of 59 m. How many Calories does he burn?
© 2010 Pearson Education, Inc.
Slide 10
Checking Understanding
When you walk at a constant speed on level ground, what energy transformation is taking place? A. B. C. D. E. Echem Ug Ug Eth Echem K Echem Eth K Eth
© 2010 Pearson Education, Inc.
Slide 11
Example Problem
How
© 2010 Pearson Education, Inc.
Slide 1
© 2010 Pearson Education, Inc.
Slide 2
© 2010 Pearson Education, Inc.
Slide 3
© 2010 Pearson Education, Inc.
Slide 4
Reading Quiz
1. A machine uses 1000 J of electric energy to raise a heavy mass, increasing its potential energy by 300 J. What is the efficiency of this process? A. B. C. D. E. 100% 85% 70% 35% 30%
© 2010 Pearson Education, Inc.
Slide 5
Reading Quiz
2. When the temperature of an ideal gas is increased, which of the following also increases? (1) The thermal energy of the gas; (2) the average kinetic energy of the gas; (3) the average potential energy of the gas; (4) the mass of the gas atoms; (5) the number of gas atoms.
A. B. C. D. E.
1, 2, and 3 1 and 2 4 and 5 2 and 3 All of 1–5
© 2010 Pearson Education, Inc.
Slide 6
Reading Quiz
3. A refrigerator is an example of a A. B. C. D. E. reversible process. heat pump. cold reservoir. heat engine. hot reservoir.
© 2010 Pearson Education, Inc.
Slide 7
Example Problem
Light bulbs are rated by the power that they consume, not the light that they emit. A 100 W incandescent bulb emits approximately 4 W of visible light. What is the efficiency of the bulb?
© 2010 Pearson Education, Inc.
Slide 8
Efficiency
© 2010 Pearson Education, Inc.
Slide 9
Example Problems
A person lifts a 20 kg box from the ground to a height of 1.0 m. A metabolic measurement shows that in doing this work her body uses 780 J of energy. What is her efficiency?
A 75 kg person climbs the 248 steps to the top of the Cape Hatteras lighthouse, a total climb of 59 m. How many Calories does he burn?
© 2010 Pearson Education, Inc.
Slide 10
Checking Understanding
When you walk at a constant speed on level ground, what energy transformation is taking place? A. B. C. D. E. Echem Ug Ug Eth Echem K Echem Eth K Eth
© 2010 Pearson Education, Inc.
Slide 11
Example Problem
How