Assignment - Individual Design & Build A model catapult

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

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.

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.

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. Summary. 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. Introduction.  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/s2 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. Conclusions. 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. References. A formal list of cited sources, if you used any. 

11. 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.

Attachment:- Assignment Files.rar