ENGR101 Organised Report ENGR101/2017 Assignment 3
Engineering
Individual Design & Build A model catapult Marks: 15% of the final course grade Due Date: Tuesday 2nd of May, 3 PM Learning Objectives: The objectives of this assignment are:to practice using established engineering/scientific theories in an experimental apparatus to communicate the results in a concise and organised engineering report Relevance It could be argued that rational design, based on sound scientific principles, is what separates professional engineers from any backyard inventor. One rather crude definition of an engineer is “a person who can do for one dollar, something that any fool can do for two�. Such a definition contains a grain of truth but, like all simplifications, it does less than justice to those engineers who find solutions to numerous non-trivial problems, such as designing supercomputers, artificial limbs, space shuttles, nuclear power plants or tall structures. Even for relatively simple devices, we would like to think that following a rational design process will result in a superior solution to that which can be obtained by relying on trial and error or uninformed inspiration! Therefore this assignment is designed to provide you with an opportunity to put into formal practice the engineering professional skills described in lectures and workshops. An engineer must be able not only to think creatively but to communicate clearly. A secondary function of this assignment is therefore to enable you to communicate your thoughts in a professional manner. 2017 ENGR101 Assignment 3 Briefing Sheet 1 Assignment Objective:
To design, build and test a model catapult that can hit the set targets. The experimental results are to be compared with the theory.
(Note: this image is for reference only. Your model catapult can be of any design or shape.) Physics involved: Physics of catapults; projectile motion; energy conservation
Tasks to complete (see Figure. 1): hit one target within a 0.1 m radius of a target that is 1 m away horizontally from the base of the model catapult. hit one target within a 0.2 m radius of a target that is 2 m away horizontally from the base of the model catapult. You need to predict and plot the theoretical trajectory based on the parameters of your own model catapult using Excel and include the figure in your report (Section 8 – Results and Discussion). You may make any assumptions if needed, but they must be clearly stated in your report. You will also need to use Excel to tabulate the effect of launch angle OR initial (launch) velocity on horizontal displacement.
Figure 1: A model catapult that launches a payload to hit a set target. In your report, you need to provide a list of materials used for building your model and their costs. The total material cost of your model must not exceed NZD 20 (Recycled materials from your yellow bin are considered free). You MUST NOT purchase a commercially available catapult model. Although your main objective is to design, build and test your catapult model, you will need to carry out rational; quantitative (with numerical results) tests first. You should carry out tests to determine how far the payload can potentially hit based on the parameters include, but not limited to, the height of the payload above the base of the catapult, the level of the catapult relative to that of the target, the weight/size/shape of the payload, the form of energy added into the system etc. Then you should test your proposed design, quantitatively if at all possible. The engineering process taught in the lectures and the workshops may be useful when you consider the problem and work towards your final design. You should use any experience gained to show at least some degree of improvement in your design during the project.
If you are in doubt about any aspect of this project, use your engineering judgement to make minor modifications to this specification and include these modifications in your report. Please do NOT email course tutors or lecturers to see if your proposed modifications or innovations are acceptable. Design Report You must hand in a formal report with a maximum length of 10 sides of A4 paper (including references, if used, but not including the cover sheet, title page, or appendices), at least 25 mm margins, and using 12 pt Times New Roman, 11-point Arial font (or close equivalent), with 1.5 line spacing. You can find the report template on Learn. You should use 3rd person, formal technical, writing. Your report should contain the following sections (see also the assessment criteria below for further information): 1. Cover Sheet. Include the assignment cover sheet with the marking schedule (included in the Word template) with all details filled in and signed to confirm that this is your own work. 2. Title Page. The title page should be a professional looking page. 3. This is a short summary (maximum of 150 words) to enable other engineers to get a quick overview of what is in the report. It should contain a brief summary of the problem statement, how you went about designing and building your model, test results and any conclusions you made. 4. Table of Contents. The table of contents should indicate the title of each section (and subsection, if applicable) and their corresponding page numbers clearly. 5. In your own words, describe the problem clearly so someone else can understand it. What will the solution accomplish? Are there imposed specifications and limitations? 6. Background/Theory. What are some of the questions that must be answered to solve the problem? For example, how would the relative height and horizontal distance between the payload (or the catapult) and the target affect the potential results? You should report on your investigation into projective motion, potential/kinetic energy, energy storage etc. within the context of building a model catapult as described in this assignment. Make sure you give appropriate citation to any new information or knowledge that you obtained during the research and investigation. Prior knowledge or obvious information such as the definition of gravitation or constant acceleration due to gravity is 9.8 m/s 2 does not need to be cited. 7. Experimental Methods. Describe how you constructed your model catapult based on specifications and limitations. You must include at least two figures that show your model catapult with all important dimensions and the actual testing conditions/environment clearly. Describe any modifications you made as a result of the construction process and how these might have altered/improved the solution. Also, describe how you tested your design to see how it performs. 8. Results and Discussion. Describe the results. Make and include a figure using the given Excel template to show the theoretical trajectory. Did your model achieve the set targets within the specifications and limitations? Explain. If it did not, explain what went wrong. (Remember, learning what doesn’t work can be as valuable as knowing what does.) If you had to solve the problem again, would you use the same approach? Why or why not? 9. Summarise whether or not your results support or contradict the original theories. Have the learning and assignment objectives being met? You may also give recommendation to your design if necessary.
10. 11.
A formal list of cited sources, if you used any. Appendices. If you wish, you may include a few extra pages (additional to the 10-page limit) here with extra information that you think is relevant to your project, such as raw data from your testing, a page or two of data sheets from the internet, etc. Appendices will not be marked so you should make sure that no essential information is included here. Hand-In Instructions Download the Assignment 3 Word template from Learn. Use this template to write the report. Hand in a hard copy of your assignment to the slot corresponding to your Workshop in the Assignment Boxes located on Level 1 of the “Core Engineering” building, in the corridor to the lecture theatres E8 and E9, see Figure 2. There is no stapler at the submission site, so staple your report before arriving!
Figure 2: Submission location for ENGR101 assignments. Also, submit an electronic version of your report on the Learn website via the heading “Assignment 3Submission”. All submissions will be checked for plagiarism using Turnitin (Turn It In) software. After submitting, click on the button “Save Changes”. You may use any software for spreadsheeting and word processing, but you
must save the report as .doc, .docx, or .pdf filetype before electronic submission to Learn as that is a Turnitin limitation. Submissions will not be marked unless they have the correct cover sheet and all details completed, including your Workshop group code. Your Workshop group number is shown in your timetable after “Wor�, see Figure 2.
Figure 3: Identify ENGR101 Workshop group numbe