## Archive for the “Subject” Category

Chapter 11. INTERNAL FORCES IN STRUCTURAL MEMBERS: ISOSTATIC PLANE BEAMS

11.1 Isostatic beams. Introduction.

11.2 Reactions at supports.

11.3 Types of loads on beams.

11.4 Internal forces in beams. Sign convention.

11.5 Loads, shears and axial forces.

11.6 Bending moments.

11.7 Graphical analysis of a beam.

11.8 Elastic curve of a beam.

You should learn to solve any isostatic plane beam after the theoretical lectures, the problem sessions and the homework you did during this part of the subject. Chapter objectives can be  summarized as follows:

• To show how to use the method of sections to determine the internal loadings in a member.
• To generate this procedure by formulating equations that can be plotted so that they describe the internal shear and moment throughout a member.
• To draw the shear and moment diagrams for any isostatic plane beam.

The next video explains how to solve a beam using the method of sections (Spanish from a Professor at the Universitat Politècnica de València).

Bibliography

Rodes Roca, J. J., Durá Doménech, A. i Vera Guarinos, J., Fonaments físics de les construccions arquitectòniques (Publicacions de la Universitat d’Alacant, Alacant, 2011). Capítol 12.

Rodes Roca, J. J., Exercicis i problemes dels fonaments físics d’arquitectura. I. Vectors lliscants i geometria de masses (ECU, Alacant, 2009)

Rodes Roca, J. J. i Durá Doménech, A., Exercicis i problemes dels fonaments físics d’arquitectura. II. Estàtica aplicada a les estructures (Col·lecció Joan Fuster 154, Universitat d’Alacant, 2013)

Tipler, P. A. i Mosca, G., Física per a la ciència i la tecnologia, Volum 1 (Reverté, Barcelona, 2010). Capítols 1 i 12.

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Chapter 10. INTERNAL FORCES IN STRUCTURAL MEMBERS: PLANE TRUSSES.

10.1 Plane trusses. Introduction.

10.2 Assumptions made in truss analysis.

10.3 Isostatic and hyperstatic systems.

10.4 Method of joints.

10.5 Method of Maxwell-Cremona.

10.6 Method of Ritter or sections.

You should learn to solve any plane truss after the theoretical lectures, the problem sessions and the homework you did during this part of the subject.

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A rigid body is said to in equilibrium if the resultant of all forces and all their moments taken about any and all points are zero.

Free body diagram (FBD): depiction of an object with ALL the external forces acting on it.

Reactions coming from the supports: usually a body is constrained against motions using supports. It is essentially to correctly estimate the number and type of reactions that a support can provide.

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This entry help you to prepare laboratory reports for all general science and engineering at PUC-EPS-UA. It describes the structure of a good laboratory report, outlines the different sections of the report, and explains the need for each of them. It also introduces some standard conventions and rules for writing reports of professional quality.

Laboratory reports will be graded not only for technical content but also for writing and style. The quality of your written report will strongly affect your grade for the course. Students are required to follow the general rules in this entry and the specific format instructions given to them by their laboratory instructor.

You can read a complete guide to laboratory report writing here or here (see below a copy) and an example here. Just you need to adapt this rules to our course.

# General Outline of a Laboratory Report

Scientific writing is just as important as scientific investigation or experimenting. Although the major part of scientific investigation takes place in the laboratory–connecting equipment together, repairing, obtaining supplies and samples, checking each apparatus for consistency, calibration, and finally data collection by running the experiment—a great deal of time is spent to present the results in a concise, objective, critical and conclusive format called laboratory report (similar to research paper). Therefore, a well-organized laboratory report is much more effective and influential than one without a structure. There is no short list of instructions for writing a good laboratory report. You may have only one chance to influence your reader. While ineffective writing can turn off the readers, a well-written laboratory report can have impacts on your reputation, chance of employment or promotion. You may also draw the attention of the scientific community to your work and retain them as your readers.

Sections of a laboratory report:

A laboratory report usually have several sections identified by titles. A typical report would include such sections as TITLE, INTRODUCTION, PROCEDURE, RESULTS, and DISCUSSION/CONCLUSION. If you are using a computer to type your work, section headings should be in boldface.

Title:

The title can usually draw attention of the reader to your work. It should clearly represent the work presented. If the purpose of the experiment is to measure the gravitational acceleration of the earth using pendulum as the experimental apparatus, the title should be like “ Measurement of the Gravitational Acceleration Using Simple Pendulum”. Avoid “The” as the first word in the title for it will lead to misleading searches when one uses the database.

Introduction:

State the purpose of the experiment in general terms. For example, “ It is possible to measure the gravitational acceleration using the oscillations of a simple pendulum.”

Review the existing information or the theory. Reader will look for some reminder of the basic information relating to this particular area. This can be done by giving him/her a brief summary of the existing state of knowledge. We can also include a summary of earlier work with proper references.

Supply a paragraph or two about how the basic information, such as an equation representing the behavior of a model (theory), can be used to make measurements.

Procedure:

Indicate what parameter or properties of the system you are measuring. Usually you change a parameter of the system (such as changing the temperature, independent variable), and measure its effect (such as the length of a metal rod, dependent variable).

Specify such measurement details as the type of standard or instrument used to make the measurement (for example, meter stick or vernier calliper, etc). Give the instrument uncertainties. For example, if we are using a meter stick, we can say, “ the length of the rod is measured using a laboratory meter stick accurate to within 1 cm. You may also give, if necessary, an apparatus diagram.

Results:

• Provide tables showing your measurement with units.
• Describe the uncertainties: standard, instrument, random errors
• Provide graphs. Graphs should be neat, clear, and include the axis label and units.
• Computation of the final answer: slope calculation, averages, and standard deviations all in proper significant figures.

Discussions/Conclusions:

• Present your findings from the experiment.
• Evaluate the outcome objectively, taking a candid and unbiased point of view. Suppose that the outcome is not close to what you expected. Even then, after checking your results, give reasons why you believe that outcome is not consistent with the expected. Make it plain, simple. Make factual statements such as “graph 1 shows a linear variation of velocity with time”.
• State the discrepancies between the experimental results and the model (theory), and discuss the sources of the differences in terms of the errors by offering logical inferences.
• Suggest improvements

Although these do not make an exhaustive list of do’s or don’ts, they nevertheless offer a framework around which one can write an effective report. In our experiment, some of the items indicated under each section may not be needed. I will give you more feedback in class. I expect that, the lab reports, either typed or handwritten, should be neat, clear, and organized. Points will be deducted for these, as well as for missing units and failing to follow the outline (i.e. title, introduction, procedure, results, conclusion) given above.

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We can say that physics is the science of the measure. Unfortunately, this means we have to learn the error analysis treatment of our data. You can download all the documents from our campus virtual at University of Alicante (in Spanish or Catalan/Valencian). Nevertheless, it could be interesting to read the Physics Laboratory Tutorial from the Columbia University as well.

We did video laboratory experiments in physics (in Spanish) you can watch by this link.

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Usually the students thought that this aspect of physics, in particular, and science, in general, is not important. However, it is not the same mistakes in an exercise on paper than on a real problem of engineering or science.

To give a value to this entry, we attached some news and the causes of the accidents that have occurred for reasons that should never happen.

1. The NASA’s mission Mars Climate Orbiter (September 1999), had a part of the engineering team working in English units (feet, inches and pounds) and another one working in the decimal metric system. Incredible but true and below are some links for verification:
1. Official site for the mission here.
2. CNN news related to this fact, here and here.
3. News on the Washington Post.
4. Or on the BBC.
2. On July 23, 1983, Air Canada Flight 143, a Boeing 767-233 jet, ran out of fuel at an altitude of 41,000 feet (12,000 m), about halfway through its flight originating in Montreal to Edmonton. Fuel loading was miscalculated due to a misunderstanding of the recently adopted metric system kp which replaced the imperial system pounds.
1. CBC digital archives.
2. Another reference in a classroom of mathematics, here.
3. News on the New York Times.
3. The Tokyo Disneyland’s Space Mountain:
4. Can you find more examples?

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The best way to learn physics is practise, practise, and practise. You need to check whether you understood all the concepts or not, therefore, try to think logically and correlate your questions with real life situations. I saw in this web-page some ideas for learning physics and other technical courses. In summary, these are some points to take it into account:

1. Never miss a class. Ever. Although you do not believe it, you can learn physics with lectures.
2. Never fail to do every problem of every assignment.
3. If you are required to hand in problem solutions, do the problem twice. The first version should go in your own notebook, along with all the failed attempts. The second should be a copy to hand in.
4. Always prepare for each class. That means have a look at what is coming up in the text or notes after you have done the assignments. Check the guide of the subject.
5. Write out your work for every problem clearly. Show every step, even if your phone mobile has 1 Gb of memory.
6. Do not ever try to erase your mistakes, just cross out with a single line.
7. Always draw a picture for each problem and label it clearly.
8. To study for tests, do problems. Write down any formulas each time you use them and you will know them by heart without any further effort.
9. Always ask for help, but make sure that you have done your part before you go to the teacher. This means that you must work out the offending problem neatly up to the point where you lose the trail.
10. All that really ever works is to review and to practise solving problems.
11. Learn to draw a good graph, properly labelled and scaled.
12. Always do your own work, especially in laboratory settings. That means preparing your own report on your own, even if the data was collected by someone else.
13. Always prepare for the laboratory: know what you are going to do and how you are going to do it.
14. Last but not least, it is important in your career to demonstrate your integrity as a student and as a person. A reputation for honesty will serve you far better than any course grade. It is incredible, isn’t?!!!!

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Welcome to the blog of Physics I: Fundamentals of Structures of the Technical Architecture Degree of the University of Alicante. Here you can look for information about this subject, and interesting links as well. We hope that this tool could be a new way to our interaction. We are working to translate all of our materials during this semester, but we know that this is a hard task and we ask for your patient.
We are also making new materials to support your learning by yourself: this is the principal aim of the European Higher Education Area (EHEA). The contents of the physics course and most of the documents we are going to use in the classroom can be downloaded from the Campus Virtual of the University of Alicante.
Bienvenidas/os al blog de Fundamentos Físicos de las Estructuras del Grado en Arquitectura Técnica de la Universidad de Alicante. En él podéis encontrar información sobre la asignatura, así como enlaces de interés. Esperamos que entre todos podamos sacarle el máximo jugo a esta nueva herramienta de comunicación.
Continuamos trabajando en la elaboración de materiales que favorecerán el aprendizaje autónomo del alumnado: objetivo fundamental del Espacio Europeo de Educación Superior (EEES). Los contenidos del curso y la mayor parte de los materiales que se utilizarán en las clases se facilitarán a través del RUA a medida que se vayan produciendo.
Benvinguts/des al bloc de Fonaments Físics de les Estructures del Grau en Arquitectura Tècnica de la Universitat d’Alacant. Ací trobareu informació sobre l’assignatura i enllaços d’interés. Esperem que entre tots puguem traure-li el màxim suc a aquesta nova eina de comunicació.
Continuem treballant en l’elaboració de materials que afavoriran l’aprenentatge autònom de l’alumnat: objectiu fonamental de l’Espai Europeu d’Educació Superior (EEES). Els continguts del curs i molts dels materials que s’utilitzaran en les classes es posaran al vostre abast a través del RUA a mesura que es vagen produint.