QUIZ 8

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

Ch 10

exercises

 5 8 13 15 28, 29 37 59

 

 

 

 

 

 

 

 

problems

 1 2 4 8 9                

 

Ch 13

exercises

 3 23 29 32 37

 

 

problems

 1 2 3

 

Real Quiz 8

Hints: HINTS WILL BE POSTED SOON….. CHECK BACK LATER!!!

 Ch. 10

exercises                            

. 5.
28, 29.
37.

 problems
2. see fig. for exercise 1. (a) H = (1/2) g t2     (b) x = vt, where v = airplane speed. (c) Directly below. Engine and plane have the same horizontal speed v.
4.


                                            x

 


find the time top drop a distance 1.3 m...see problem 2. then use the relationship between x  , the time, and v. (Hint: see the last lab you did.)

 Ch. 13

 exercises
23. N is the normal force= force of stony beach floor on the bottom of your feet. FB is  the buoyant force. These two forces must balance  the weight mg:   N + FB = mg. Thus, N = mg - FB . In other words,  the force of the beach floor  on the bottom of your feet reduced by the buoyant force.

32. The statement in the book is totally inaccurate. Take the Titanic before  it hit those ice bergs. That ship was hecka heavy and floated. On the other hand, take a concrete brick that is clearly much lighter than a big ship. The brick will sink. Why?. Check out the pictures below: Ship weight Mg > mg since the Titanic  is very heavy compared to the brick of weight mg. But the buoyant force fB for the brick < mg, which is why the it  sinks. Remember the buoyant force is the weight of the water displaced by the object.  For the ship, the buoyant force is huge ! Why? Because a huge amount of water is displaced by the inside of the ship. The weight of this water is a huge  FB which is able to balance the huge weight of the ship:  FB = Mg, which is why the ship floats
37. Below is the barge with iron scrap of weight mg before it is thrown overboard; the weight of the barge = Mg, and the buoyant force is FB. FB must balance the weight of the barge and the weight of the scrap: FB = Mg + mg. Now when you throw the scrap overboard FB will change to a smaller value FB' where FB' = Mg. Will the volume under the dashed line increase or decrease. Hint: FB' = weight of water displaced after the scrap it thrown  over board. Will this volume increase or decrease if the buoyant force is decreased, and how will the water level at the side of the barge change???

problems
2. density = mass/volume, where the mass and the volume are given. Note 1 L = 1000 cm3 = 1000 (10-2 m/cm)3 =
10-3 m3 .