QUIZ 3 

Exercises and Problems from Conceptual Physics: Note that answers to odd numbered problems are listed in the paperback supplement "Practicing Physics." 

Ch 6 
exercises 
impulse 
2 
4 
8 
momentum 
13 
16 
42 








problems 
impulse 
2 
3 
momentum 
6 
7 
9 







Ch 7 
review questions 
10 
exercises 
15 (see fig 7.12) 
20 
21 
28 
30 
48 
50 
54 







problems 
2 
4 













exercises 

2. large time means small force...see fig 6.5.. 

4. fig. 6.5  
8.  Impulse  = I =  change in momentum  = mv = Ft so that v = Ft/m. Now, the force F that kills a person and the mass m are fixed numbers. The difference is the time t.  
13. momentum = mv. Does m change???  
16. see fig. 6.11  


2. mv = Ft.  
6 



exercises 

21. The direction of motion shown. It is NOT horizontal. The weight, of magnitude mg, points down. The two components of this downward vector are shown. One is along the motion. This force component does work on the object moving in that direction. The other is perpendicular to the component along motion. If the motion was horizontal, there would be NO component of gravitation force along the motion, and no work  
30.Same speed. On the the bottom track, as it goes down the middle dip, the second ball gains more kinetic energy than the first ball, but loses the same amount of kinetic energy again after the leaving the dip. 

54 .Momentum is conserved. See. Fig 6.15. Kinetic energy is not conserved since the objects come to rest... 

Problems 





