Peoples Physics Book Version-2

http://www.ck12.org Chapter 2. Energy ConservationVersion 2

c. If 0.15 gallons were used up in the process, what is the energy content of the gasoline in Joules per

gallon?

12. A pile driver’s motor expends 310,000 Joules of energy to lift a 5400 kg mass. The motor is rated at an
    efficiency of 0.13 (see 11b). How high is the mass lifted?

Answers to Selected Problems

1. d


2. (discuss in class)
   
   
   1. 
      
      
      
      5. 0 × 105 J
      
      
      
      
   
   
   2. 
      
      
      
      3. 7 × 105 J
      
      
      
      
   
   
   3. Chemical bonds in the food.
   
   
   4. 99 m/s
   
   
   5. 
      
      
      
      5. 0 × 105 J
      
      
      
      
   
   
   6. 108 m/s
   
   
   7. 450,000 J
   
   
   8. 22,500 J
   
   
   9. 5,625 J
   
   
   10. 21.2 m/s
   
   
   11. 9.18 m
       3..
   
   
   
   


3. b.KE= 504 ,600 J;Ug= 1 , 058 ,400 J;Etotal= 1 , 563 ,000 J
   
   
   1. 34 m/s at B; 28 m/s at D,40 m/s at E,49 m/s at C and F; 0 m/s at H
   
   
   2. 96 m
   
   
   3. 1.7 J
   
   
   4. 1.3 m/s
   
   
   5. 0.4 J, 0 .63 m/s
   
   
   6. 1.2 m/s^2
   
   
   7. 130 J
   
   
   8. 6750 J
   
   
   9. 
      
      
      
      2. 25 × 105 J
      
      
      
      
   
   
   10. 
       
       
       
       1. 5 × 105 J/gallon of gas
       
       
       
       
   
   
   
   


4. 0.76 m