Homework

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Homework problems are taken from the 6th edition of Serway and Jewett text. 

The due dates/day for the homework, along with the problem numbers, are listed below.  Problems in bold red are graded in detail out of 5 points each.  The rest are graded out of 2 points.  An almost correct solution or a valiant attempt gets 2 points while a decent attempt with the right method and equations and some progress, gets 1 point. 

Please make sure that all answers have the proper units.

Week

Hw #

Date

Day

Problems

Week 1

 

June 4

Monday

 

 

 

June 5

Tuesday

 

 

1

June 6

Wednesday

1.3, 1.20, 1.31, 1.54, 2.1, 1.5, 1.55

 

2

June 7

Thursday

2.5, 2.11, 2.12, 2.21, 2.27, 2.42,
2.43, 2.63                                          

 

3

June 8

Friday

3.1, 3.9, 3.25, 3.31, 3.36, 3.47, 3.34, 3.59

 

 

 

 

 

Week 2

4

June 11

Monday

1.18, 1.50, 2.6, 2.10, 2.40, 4.1, 4.2, 4.5, 4.10, 4.19, 4.58, 4.67, 4.21, 4.54

 

5

June 12

Tuesday

5.1,5.2,5.3,5.7,5.9,5.11,5.14 (Refer to hints under the section "Answers to EVEN numbered problems"

 

 

June 13

Wednesday

 

 

6

June 14

Thursday

5.18,5.19,5.22, 5.23, 5.41, 5.45

 

7

June 15

Friday

5.24, 5.25, 5.37, 5.44, 5.46

       

Week 3

8

June 18

Monday

4.33, 4.34, 4.35, 6.1, 6.5, 6.9, 6.11, 6.13, 6.15, 6.19, 6.20, 6.61, 6.63, 6.65, 6.71

 
9
June 19 Tuesday
7.5, 7.10, 7.11, 7.19, 7.25, 6.58
 
10
June 20 Wednesday
5.54(ignore d),5.57,7.31,7.33,7.34,8.5,8.26
 
11
June 21 Thursday
7.53, 8.10, 8.13, 8.24, 8.31, 8.36, 8.37

 

12
June 22 Friday
6.18, 6.17, 8.30, 8.33, 7.56, 8.11, 8.17, 8.30, 8.33
       
Week 4
13
June 25
Monday
8.48, 8.57, 8.59, 8.61, 8.63, 8.65, 8.73, 8.66
 
14
June 26
Tuesday
9.1, 9.3, 9.7, 9.9, 9.10, 9.17, 9.18, 9.20
 
15
June 27
Wednseday
9.24, 9.28, 9.38, 9.41, 9.67,
 
16
June 28
Thursday
15.2, 15.3, 15.9, 15.11, 15.13, 15.16, 15.18, 15.21, 15.23
 
17
June 29
Friday
15.5, 15.53, 15.28, 15.32, 10.1, 10.3, 10,4, 10.7, 10.20, 10.21
 
Week 5
18
July 2
Monday
10.31, 10.34, 10.37, 10.38, 10.46, 10.70, 10.71, 11.3, 11.11, 11.30, 11.28, 11.36, 11.50
 
19
July 3
Tuesday
12.43, 12.45, 12.49, 12.55, 13.2, 13.3, 13.15, 13.19, 13.39, 13.43 (a,b,c only)
     
 
20
July5
Thursday
14.6, 14.8, 14.12, 14.18, 14.20, 14.24, 14.25, 14.27, 14.29, 14.48, 14.51
 
21
July6
Friday
16.2, 16.9, 16.17, 16.27, 16.31
         
Week 6!
22
July 9
Monday

16.30, 16.39, 16.47,16.50, 18.5, 18.13, 18.19, 18.21,18.27 (REVIEW PROBLEMS: 2.63(with the exam twist),2.43, 4.21, 4.54,4.67, 5.54,5.44)

 
23
July 10
Tuesday

16.32,16.57,16.62,18.14, 18.17, 18.37, 18.41,18.43,17.37 (Review problems: 6.61, 6.63, 6.65, 7.33, 8.61,8.65,15.53,14.20)

  24
July 11
Wednseday

14.48, 14.51, 14.38, 14.48, 17.19, 17.18, 17.39, 17.60, 19.1, 19.2, 19.5, 19.6, 19.15, 19.16, 19.18 (REVIEW PROBLEMS: 12.43,11.36,example 11.8, 10.70, 9.67, 9.24)

 
25
July12
Thursday
19.45, 19.46, 19.50, 19.56, 20.7, 20.11, 20.18, 20.16, 20.24, 20.38, 20.23 (REVIEW 8.33, 8.57,15.11, 15.19,6.60)
 
26
July13
Friday
13.2, 13.15, 13.19, 13.39, 20.30, REVIEW problems (Derivation eq-10.29, eq-10.30, quick quiz 10.12,10.13, 10.14, 11.30,
         

 

Questions and Solutions.

Some students are using the 7th addition. The table below has the links to the pdf files of the questions and answers to each homework.

Week

Hw #

Date

Day

Questions

Answers

Week 1

 

June 4

Monday

 

 

 

June 5

Tuesday

 

 

1

June 6

Wednesday

HWQ1

 

2

June 7

Thursday

 

3

June 8

Friday

 

 

 

 

Week 2

4

June 11

Monday

 

5

June 12

Tuesday

 

 

June 13

Wednesday

 

 

6

June 14

Thursday

 

 

7

June 15

Friday

 

           
Week 3
8
June 18 Monday
 
9
June 19 Tuesday
 
10
June 20 Wednesday
 
11
June 21 Thursday
 
12
June 22 Friday
           
Week 4
13
June 25 Monday
 
14
June 26 Tuesday
 
15
June 27 Wednesday
HWAns15
 
16
June 28 Thursday
HWAns16
 
17
June 29 Friday
HWAns17
           
Week 5
18
July 02 Monday
 
19
July 03 Tuesday
 
       
 
20
July 05 Thursday
HWAns20
 
21
July 06 Friday
HWAns21
           
Week 6
22
July 09 Monday
 
23
July 10 Tuesday
 
24
July 11 Wednesday   HWAns24
 
25
July 12 Thursday
HWAns25
 
26
July 13 Friday
HWAns26
           


Answers to Even numbered problems

Homework # 4

1.18.   35.7 m2 .
4.10.   7.23× 103 m, 1.68× 103 m
4.58. 7.50 m/s (in what direction? You have to specify)
4.54 10.7 m/s

Homework # 5

HINTS:

5.2.   1.66× 10^6 N
5.14.  a) 181 degrees Counteclockwise from X axis, b) 11.2 Kg, c) 37.5 m/s at 181 degrees
5.11 (Hint) Write the forces in vector notation. Use F=ma and find a in vector notation. FInd magnitude
and direction of a. Or you could find the resultant of F1 and F2 and then find acceleration.

Homework # 7

5.24.   s=6.3 m/s^2 T=31.5 N
5.44. a=2.31 m/s^2 down for m1, left for m2, up for m3, T between m1 and m2=30.0 N, Tm2<->m3=24.2 N  
5.46. Pmax=48.6 N, Pmin=31.7 N

Homework # 8

4.33.   1.48 m/s^2, 29.9 degrees
4.34  a) 0.6 m/s^2 b)Radial acce =0.8 m/s^2,c) Resultant acc= 1.00m/s^2, 53.1 degrees
6.20  a) 8.62 m b) Mg downward, c) 8.45 m/s^2                                                                   
6.61 (Hint)c) The freebody diagram is more like in the case of a banked curve where the forces acting are just N and mg. But N is at an angle so that the horzontal component of N is along the radius an dthe vertical component of N balances Mg. so figure theta out.

6.65 Time period of revolution is distance/velocity T= (2*Pi*r)/v. Frequency is 1/T and is in units revolutions/second. convert that to revolutions/min.

Homework # 10

5.54.   a) a=2.00 m/s^2, b) 8.00 N on 4kg block, 6.00 N on 3kg, 4.00 N on 2kg c) 8.00 N and 14.0 N
7.34  a) 329J b)0J,c) 0 d) 185J e)+144J
8.26  a) 22J, 40 J                                                                   

Homework # 13

8.66.   k=7.2*10^2 N/m v= 0.923m/s

Homework # 14

9.10.   a) I=5.40i N.s, b) W=-27.0J
9.18  a) Vf=2.50 m/sb)Kf-Ki=-3.75*10^4 J
9.20  a) hmax=0.556 m (the velocity of m1 just after collision works out to be -3.30m/s)

Homework # 15

9.24. v=(4M)Sqrt(gl)/m  
9.28  a) theta=32.3 deg, V=2.88 m/sb)Kf-Ki=783J
9.38  a) Xcm=0, Ycm=1.00m

Homework # 17 – Friday

15.28 gc/gt= Lc/Lt =1.0015
15.32 T=3.65s b) 6.41 s c)4.24s
10.4   a) 1200 rad/s b)25.0 s
10.20  a) 92 kg m^2m KErot=184 J b) v1=6m/s v2=4m/s, v3=8 m/s.    KE1=72 J
KE2= 16.0 J KE3= 96.0 J Ktot= 184  J

Homework # 18 – Monday

10.34 a) 1.03 seconds, b) 10.3 rev
10.38  coefficient of kinetic fric= 0.312 (USE torque equation since friction provides the torque that slows it down)
10.46  Use conservation of energy along with rotation to find v=2.36 m/s
10.70  Omega= Sqrt[(2*m*g*d*sin(theta)+k*d^2)/(I+m*R^2)]
11.28  ωf =(I1/( I1 +I2))* ωi  . b) Kf/Ki = I1/( I1 +I2)
11.30  a) 1.91 rad/s  b) Ki=2.53 J Kf= 6.44 J
11.36  apparent acceleration is “Radial or centripetal acceleration” = 12.3 m/s^2
11.50  WILL DO IT IN CLASS TODAY

Homework # 20

14.6 Guage pressure is the difference between the absolute pressure (which could include the atmospheric pressure) and the atmospheric pressure. A) P= 1.01 *10^7 Pa B) 1.0*10^7Pa
14.8 F2= 225 N
14.10 Fb= 5.88 *10^6 N F= 196 kN on each end. F= 588 kN on each side
14.12  a)20.0 cm, Use density = mass/volume ,and volume = area*height
b) Use the fact that the amount of water below the horizontal level is the same as the volume of mercury above the level. So A1*h= A2*h_below
and then use the fact that the pressure at the lowest point of water  is the same as the pressure at the same level on the other side. (ALL mercury below that level). Pressure on right is just due to water above and on left is just due to mercury. Using these two equations solve for  h. =0.490 cm
14.20 h1=12.6 cm similar logic as above.  Call the height in the middle as some h and that will cancel out when you equate pressure on both sides. Choose a level where the liquid below that level is the same on both sides.
14.24 A= m/[(Rho_water-Rho_styrofoam)*h]
14.48 P2= 6.8*10^4 Pa (DUE FRIDAY)

Homework 21.
16.30 v= 30.4*sqrt(m) b) 3.89 kg
16.50a) 21 ms b) 1.68 m

Homework 22.
16.32 v= sqrt(m L tan(theta)/4Mg) b) find t using distance/vel.
16.62 a) 5 m/s +x b) 5 m/s in –x c) 7.5 m/s – x dirn. d) 24.0 m/s +x dirn.
18.14 a) find where the nodes are in terms of pi. B) ymax = 0.0294 m

Homework 24
14.48 6.8*10^4 Pa
14.38 12.8 kg/s  use dm/dt= density*Volume flow rate
14.18,19, NOT DUE
17.39  write two equations for observed frequency. One for approach and one for going away. Use the two equations and find the siren frequency and ambulance speed.
17.60 First step calculate the frequency that the insect hears. Who is the observer who is the source? Next step insect’s body acts as the source and reflects the sound. Calculate the frequency of the echo the bat hears. Who is the observer ?
19.6 Tc=1.33Ts+20
19.16 delta A= 0.109 cm^2,
19.18 T=437oC.b)3000oC will it work? What could happen before that?

Homework 25.
19.45. Find out how much the rod contracts by and do the same for the tape. The difference is the change in the reading. So if rod contracts  more by x amount, then the reading is .950-x

19.46. Find out what the mass m of 10 gallons is at 0 degrees. At 20 degrees the 10 gallons (Vo) becomes some new V gallons. So V gallons at 20 degrees are m kg. so
How much mass do 10 gallons have? What is the difference between this and m?
0.523 kg.

19.50   use P1V1/T1 = P2V2/T2 .
The new volume is V1 + Ah. New pressure has increased since the compressed spring exerts a force. Find the excess pressure . = P1+ kh/A.  Solve for h.= 0.169 m, P2=1.35 *10^5 Pa.

19.56. Length expands. Find new time. Find the time lost per sec. a) delta T= 9.5*10^(-5) seconds. find the time lost per week. 57.5 seconds.

20.7.  Is interesting! You do not know if  Aluminum will rise in temperature or drop in temperature. Find the heat needed for water to go up to 26 degrees. Call it Qw. Find the heat lost by copper to come to 26 degrees. Call it Qc. If Qw >Qc then the copper cannot take the water beyond 26 degrees. So the temperature is less than 26 and aluminum cools.
If Qw<Qc, then the temperature is more than 26 degrees. So once you know what the situation is you know if aluminum gains or loses heat!

 

20.16, 12.9 g of steam

20.18 Temperature is 40.4 degrees. SO all ice melts. You have do show it as done in class. B) 8.04 grams melts.

20.24 a) -12 *10^6 J b) +12 *10^6 J

20.38 a) -4PiVi b) Delta Eint=0, Q=-W c) W=-9.08kJ. use ideal gas law.


 

 

 
 
 
 
 
 
 
 
 
 
 
   
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