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DO NOW Sept 16

Work with your Catapult teams. BRAINSTORM for 10 minutes about websites and ideas you have found through your RESEARCH. Ask yourselves which part of the project will be most challenging for you. GET ORGANIZED!!!. DO NOW Sept 16. CATAPULT CHALLENGE. STEM Trimester 1 2013.

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DO NOW Sept 16

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  1. Work with your Catapult teams. • BRAINSTORM for 10 minutes about websites and ideas you have found through your RESEARCH. • Ask yourselves which part of the project will be most challenging for you. • GET ORGANIZED!!! DO NOW Sept 16

  2. CATAPULT CHALLENGE STEM Trimester 1 2013

  3. You will work in your teams to complete this project. CATAPULT CHALLENGE TEAMS

  4. Watch the following video documenting the tedious and very demanding process of building a medieval trebuchet. • These boxes are labeled with each step of the EDP. How to build a catapult in eight easy steps

  5. Which velocity is most important when designing a catapult? • Explain your answer. DO NOW Sept 17

  6. Both Vx and Vy are equally important. • Equal horizontal and vertical velocities will provide the projectile with the maximum distance in travel. • If Vx is greater than Vy, the projectile’s trajectory will push it downward into the ground. • If Vy is greater than Vx, the projectile’s trajectory will push it upward causing it to lose energy. • How do you achieve equal horizontal and vertical velocities? DO ANSWERED SEPT 17

  7. http://www.youtube.com/watch?v=5WDiW1WDyrA MEDIEVAL SIEGE

  8. Take out your Measurements Worksheet and Scale Drawings DO NOW Sept 20

  9. BIG QUESTION: How can energy be used to launch a projectile? • DO NOW • 1. Review Measurements and Scaling • 2. Catapult Physics – Forces • 3. Conclusion of Medieval Siege Video Clip • 4. Catapult Teams – Presentations AGENDA Sept 20

  10. Catapults use stored energy to hurl a projectile without the use of an explosive charge. The three primary energy storage mechanisms are tension, torsion, and gravity. (Real-World Physics) THE PHYSICS OF A CATAPULT

  11. Tension is the pulling force exerted by a string, cable, chain, or similar solid object on another object. • Tension is the opposite of compression force. • Measured in Newtons (N). • PE when drawn or taut (C) • Energy = 0 at rest (B) • KE when released (A) TENSION

  12. Bows and Crossbows • Composite bow is a traditional bow laminated together. • When the bow is drawn, the sinew (stretched on the outside) and horn • (compressed on the inside) store • more energy than wood for the • same length of bow. Examples of Tension

  13. Muscle Fibers create tension during a muscle contraction. • Muscle fibers slide across one another producing tension. Examples of Tension

  14. Torsion is the twisting of an object due to an applied torque. • Torque is a rotational force. • An object tends to rotate about a fixed object. Torque = Force x Lever Arm Distance TORSION

  15. Torque

  16. Flexible elastic object that stores mechanical energy when it is twisted. • Torsion bar suspensions Examples of Torsion

  17. Examples of Torsion

  18. A counterweight is an equivalent counterbalancing weight that balances a load. Counterweight

  19. When a counterweight is greatly overbalanced on one end of a lever, it can produce large amounts of energy. Potential Energy vs. Kinetic Energy Counterweight is not moving vs. moving. Counterweight

  20. Catapults work by storing energy in twisted ropes. • They function much like an archery bow. • The tension stored is released as kinetic energy. The Mangonel Catapult

  21. The trebuchet uses a counter-balance weight to rapidly rotate the throwing arm when the weight is released. The Trebuchet

  22. The twisted rope is commonly referred to as a torsion bundle. • It consists of several lengths of rope with the arm inserted in between them. • The rope is then twisted manually on both sides of the arm using levers. • Upon release, the torsion bundle rotates the arm at high speed, launching the payload. Generating Energy

  23. List the eight steps of the EDP. • Which step do you believe is the most important to the success of your Catapult Challenge? • Explain your answer. DO NOW Sept 23

  24. DO NOW ANSWERED

  25. Big QUESTION: How do the steps of the EDP assist you in building a successful catapult? • 1. DO NOW • 2. Project Presentations: DUE THURSDAY SEPT 26 • ALL TEAMS MUST BE PREPARED TO PRESENT ANY TEAM NOT READY WILL LOSE 20% of THEIR GRADE. • 3. Media Center • 4. Practice your presentations!!! AGENDA Sept 23

  26. 1. All teams should finish their presentations first. • 2. I will check with every team in the Media Center to make sure you are on task. • 3. I am looking for completed presentations including diagrams, video clips, animations, as well as an order of presentation. Slides each team member will be presenting. Know your information. PRACTICE. Being unprepared will affect your grade. • 4. All team members must have a copy of the presentation. Being ABSENT is NOT an EXCUSE!!! • 5. Continue with your RESEARCH. BE ORGANIZED! Media Center Expectations for Sept 23

  27. You are asked to design a new touring bicycle for the US Postal Service team. • Describe how you would go about this process. Use EDP as a framework DO NOW Sept 24

  28. Find out if the riders have any specific requests (Step 1) • Determine a budget, building materials, and how quickly they need it (2). • Research existing models and share new ideas. Collect data on what works (3). • Choose a few ideas to develop. Different frame materials (aluminum, titanium, carbon fiber). Notes and drawings (4) DO NOW ANSWERED

  29. List pros and cons of each bicycle design (5). • Pick the best idea with your team. Use multiple parts from different ideas (Frame material from one idea and frame geometry from another idea 6). • Build a bike. Does it all fit together? (7) • Get out and RIDE! Make improvements based upon rider feedback, input, suggestions (8)

  30. BIG QUESTION: How does engineering evolve to build safer machines? • 1. DO NOW • 2. Presentations DUE THURSDAY SEPT 26 • 3. The duty of responsible engineering • 4. Introduce New Engineering Critique Project • 5. Closing Thoughts and Review AGENDA Sept 24

  31. The role of the engineer is to respond to a need by building or creating something along a certain set of guidelines (or specifications) which performs a given function. • Devices, plans, or creations should perform its function without fail. Engineering

  32. Engineers must struggle to design in such a way as to avoid failure, and, more importantly, catastrophic failure. • Result in loss of property, damage to the environment, and possibly injury or loss of life. • With analysis and study of engineering disasters, modern engineering designers can learn what not to do and how to create designs with less of a chance of failure. Engineering

  33. http://www.youtube.com/watch?v=SmyLgg15aKU • 8:52 Engineering Disasters

  34. What are the general opinions and fears of the public? Disasters are identified by the public’s perception of risk. Modern Engineering

  35. In 1992, roughly the same number of fatalities occurred (in the United States) in transportation accidents involving airplanes (775), trains (755), and bicycles (722). • Public perception of risk is by far the greatest with air travel. Perception of Risk

  36. January 28, 1986 • The Challenger disintegrated 73 seconds into its flight after lift-off. • All 7 crew members were killed. Space Shuttle Challenger

  37. The O-rings, as well as many other critical components, had no test data to support any expectation of a successful launch in such conditions. The lowest safe launch temperature was confirmed at 4o degrees F. The morning of the launch was 18 degrees F.

  38. Insufficient knowledge ............................... 36% Underestimation of influence ......................... 16% Ignorence, carelessness, negligence .................. 14% Forgetfulness, error ................................. 13% Relying upon others without sufficient control ....... 9% Objectively unknown situation ........................ 7% Unprecise definition of responsibilities ............. 1% Choice of bad quality ................................ 1% Other ................................................ 3% Conducted by the Swiss Institute of Technology, Zurich Causes of Failure

  39. http://www.matscieng.sunysb.edu/disaster/

  40. BIG QUESTION: How do research and brainstorming contribute to the overall success of your catapults? • 1. Finish PRESENTATIONS!!! • 2. Discuss Alternate means of firing. • 3. Continue on Scale diagrams and materials. • 4. Check-In with each team – Ask questions, be ready to show me your progress on your diagrams and specs. • 5. Homework: ENGI Disasters Topic due MONDAY AGENDA SEPT 27

  41. Look into different methods of launching your projectiles. • If your first torsion design is unsuccessful, have a secondary means to create the force necessary to launch the golf ball. • How might you be able to accomplish this? Alternate Means of Firing

  42. The Mangonel Catapult

  43. Develop some type of tension mechanism to accomplish this task. • Consider a Crossbow and its basic functions. • Keep in mind, you still need to work within your constraints when considering this second design. • Design it using the same materials available to you. • You will be able to make changes as you build it. (STEP 7) TENSION

  44. What is the equation of the Pythagorean Theorem? Question of the Day

  45. Given a right triangle with side A equal to 12 inches in length and angle A equal to 60 degrees, find the length of side B. DO NOW

  46. http://www.khanacademy.org/math/trigonometry/basic-trigonometry/basic_trig_ratios/v/example--trig-to-solve-the-sides-and-angles-of-a-right-trianglehttp://www.khanacademy.org/math/trigonometry/basic-trigonometry/basic_trig_ratios/v/example--trig-to-solve-the-sides-and-angles-of-a-right-triangle Solving Right Triangles

  47. Sin (theta) = b / c Cos (theta) = a / c Pythagorean Theorem

  48. http://science.howstuffworks.com/transport/29341-extreme-engineering-maglev-train-video.htmhttp://science.howstuffworks.com/transport/29341-extreme-engineering-maglev-train-video.htm • Watch the following video clip. • After you have watched the clip, write some pros and cons of this new engineering marvel. • Consider factors such as safety, cost, and public perception of risk. • Write down your own opinion of this technology. DO NOW Feb 10

  49. A method for propelling vessels using only electric and magnetic fields with no moving parts. • Electrification of the propellant (gas or water) can then be directed by a magnetic field, pushing the vehicle in the opposite direction. • http://www.youtube.com/watch?v=NEmgSpJK9qQ MHD Propulsion

  50. Top: US Navy Testing of Rail Gun Technology Left: Yamato 1 Seacraft and MHD Drive Engine Magnetohydropropulsion (MHD)

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