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Engineering Worksheet: Strong Shapes

Engineering lesson 17: Strong shapes: triangles, arches and beams · Set 458 · 40 questions
TalentJR

Engineer's tip (Triangles stay put): Triangles are rigid; trusses, towers and frames use them. A pin-jointed frame with n sides needs n − 3 corner-to-corner braces; a row of n triangles uses 2n + 1 straws. Arches squeeze (compression); beams span gaps; domes are arches turned round in a circle.

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  1. 1.🔺 One side of a straw bridge is a row of 5 triangles standing point-up and point-down in turn, each sharing a side with the next. How many straws does it use?
  2. 2.Which of these uses a dome? (a) an old stone bridge (b) a slab over a canal (c) a bicycle frame (d) a planetarium roof
  3. 3.🔺 A frame shaped like a triangle is made of straws joined by loose pins, with 0 corner-to-corner braces. Is it rigid or wobbly? (a) rigid (b) wobbly
  4. 4.🔺 A flat frame has 9 straight sides joined by loose pins at the corners. What is the least number of corner-to-corner braces needed to make it rigid?
  5. 5.🔺 Why can an arch carry heavy loads? (a) it is hollow (b) it bends easily (c) it is very light (d) it works in compression
  6. 6.Which of these uses triangles? (a) a crane arm (b) a curved stone doorway (c) a lintel over a door (d) a shelf on two brackets
  7. 7.True or false: an igloo uses a beam. (a) False (b) True
  8. 8.🔺 A flat frame has 4 straight sides joined by loose pins at the corners. What is the least number of corner-to-corner braces needed to make it rigid?
  9. 9.True or false: a round palace roof uses an arch. (a) True (b) False
  10. 10.True or false: an old stone bridge uses an arch. (a) True (b) False
  11. 11.🔺 Which strong shape does a shelf on two brackets use? (a) triangle (b) dome (c) arch (d) beam
  12. 12.🔺 Which shape keeps its shape best when its corners are pinned? (a) triangle (b) hexagon (c) square (d) rectangle
  13. 13.True or false: a slab over a canal uses an arch. (a) False (b) True
  14. 14.🔺 One side of a straw bridge is a row of 1 triangle standing point-up and point-down in turn, each sharing a side with the next. How many straws does it use?
  15. 15.🔺 Which strong shape does a bicycle frame use? (a) arch (b) beam (c) triangle (d) dome
  16. 16.🔺 One side of a straw bridge is a row of 8 triangles standing point-up and point-down in turn, each sharing a side with the next. How many straws does it use?
  17. 17.Which of these uses triangles? (a) a planetarium roof (b) a plank over a drain (c) an electric pylon (d) an igloo
  18. 18.True or false: a curved stone doorway uses an arch. (a) False (b) True
  19. 19.Which of these uses triangles? (a) a bicycle frame (b) a plank over a drain (c) a slab over a canal (d) an igloo
  20. 20.True or false: a crane arm uses a beam. (a) True (b) False
  21. 21.True or false: a round palace roof uses a dome. (a) False (b) True
  22. 22.🔺 Which strong shape does a lintel over a door use? (a) triangle (b) arch (c) beam (d) dome
  23. 23.🔺 A frame shaped like a hexagon is made of straws joined by loose pins, with 2 corner-to-corner braces. Is it rigid or wobbly? (a) rigid (b) wobbly
  24. 24.🔺 One side of a straw bridge is a row of 13 triangles standing point-up and point-down in turn, each sharing a side with the next. How many straws does it use?
  25. 25.Which of these uses a dome? (a) a shelf on two brackets (b) an igloo (c) a bicycle frame (d) a fort gateway
  26. 26.True or false: a truss bridge side uses triangles. (a) False (b) True
  27. 27.🔺 Which strong shape does a round palace roof use? (a) arch (b) triangle (c) dome (d) beam
  28. 28.Which of these uses a dome? (a) a roof truss (b) a bicycle frame (c) a round palace roof (d) a truss bridge side
  29. 29.🔺 Which strong shape does a fort gateway use? (a) triangle (b) arch (c) dome (d) beam
  30. 30.🔺 One side of a straw bridge is a row of 12 triangles standing point-up and point-down in turn, each sharing a side with the next. How many straws does it use?
  31. 31.True or false: a roof truss uses triangles. (a) False (b) True
  32. 32.Which of these uses an arch? (a) a bicycle frame (b) a planetarium roof (c) an electric pylon (d) a curved stone doorway
  33. 33.🔺 One side of a straw bridge is a row of 2 triangles standing point-up and point-down in turn, each sharing a side with the next. How many straws does it use?
  34. 34.🔺 How do engineers stop a square frame from wobbling? (a) paint it (b) add a diagonal brace (c) make it bigger (d) take off a side
  35. 35.True or false: an old stone bridge uses a beam. (a) True (b) False
  36. 36.🔺 One side of a straw bridge is a row of 11 triangles standing point-up and point-down in turn, each sharing a side with the next. How many straws does it use?
  37. 37.True or false: a fort gateway uses an arch. (a) False (b) True
  38. 38.Which of these uses an arch? (a) a roof truss (b) a lintel over a door (c) a crane arm (d) an old stone bridge
  39. 39.🔺 A flat frame has 11 straight sides joined by loose pins at the corners. What is the least number of corner-to-corner braces needed to make it rigid?
  40. 40.True or false: a shelf on two brackets uses a dome. (a) False (b) True

Answer key

  1. 11
  2. a planetarium roof
  3. rigid
  4. 6
  5. it works in compression
  6. a crane arm
  7. False
  8. 1
  9. False
  10. True
  11. beam
  12. triangle
  13. False
  14. 3
  15. triangle
  16. 17
  17. an electric pylon
  18. True
  19. a bicycle frame
  20. False
  21. True
  22. beam
  23. wobbly
  24. 27
  25. an igloo
  26. True
  27. dome
  28. a round palace roof
  29. arch
  30. 25
  31. True
  32. a curved stone doorway
  33. 5
  34. add a diagonal brace
  35. False
  36. 23
  37. True
  38. an old stone bridge
  39. 8
  40. False

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