Exam 2 Report 11/8/2010

1

Exam 2 Report 11/8/2010

1. Summary

Total number of students 12

Attended 12

Missed 0

Number of problems 3

Average grade 75.8

Standard deviation of grades 13

2. Grade distribution

3. Comparison with past years

0 0 0

1

3

4

2 2

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

0-30 30-40 40-50 50-60 60-70 70-80 80-90 90-100

Number of Students

Grade

Total Grade Distribution

75.8 80.7 83.2 82.5 85.1 81.9 83.0 85.8 81.2

13.0 11.0 8.6 12.0 12.3 13.4 9.5 10.9 14.9

0.0 20.0 40.0 60.0 80.0 100.0

2018 2017 2016 2015 2014 2013 2012 2010 2009

Grade

Year

Comparison with Previous Years

Average Standard Deviation Average Over 2009-2018

2 4. Individual problem breakdown

5. Grade distribution per problem

7.60 7.45

8.29

1.14 1.71 1.31

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00

1 2 3

Grade

Problem

Individual scores per problem

Average

Standard Deviation

0 0 0

1

4

3 3

1 0

1

0

1

2

3 3

1

0 0 0 0

4

2 2

4

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

0-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10

Number of Students

Grade

Grade distribution per problem

P1 P2 P3

3 6. Comments

• Many students did not complete problems due to difficulty and/or time constraint PROBLEM 1

• Some students did not neglect the inertial term

• Many students incorrectly neglected ^{𝑣𝑣𝑟𝑟}

𝑟𝑟² and/or ¹

𝑟𝑟

𝜕𝜕

𝜕𝜕𝑟𝑟

�𝑟𝑟

�

• Most students had difficulty substituting 𝑣𝑣_𝑟𝑟 = 𝑓𝑓(𝑧𝑧)/𝑟𝑟 into simplified PDE and solving for 𝑣𝑣_𝑟𝑟 PROBLEM 2

• Most students had difficulty applying the moment of momentum equation

• Many students neglected the y-moment of momentum component at section 3

• Many students neglected the pressure force

• Some student did not use energy equation to calculate pressure at section 2 PROBLEM 3

• Some students incorrectly assumed friction factor is the same for all pipes

• Some students incorrectly assumed the velocity is the same for all pipes

• Some students did not assume same loss for parallel pipes A and B (i.e.

�ℎ

�

= �ℎ

�

→

�𝑓𝑓

�

𝐴𝐴

= �𝑓𝑓

�

𝐵𝐵

)