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Engineering Worksheet: Strong Shapes

Engineering lesson 17: Strong shapes: triangles, arches and beams · Set 389 · 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.🔺 Which strong shape does a plank over a drain use? (a) arch (b) beam (c) dome (d) triangle
  2. 2.🔺 Why can an arch carry heavy loads? (a) it works in compression (b) it bends easily (c) it is very light (d) it is hollow
  3. 3.🔺 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?
  4. 4.🔺 A frame shaped like a pentagon is made of straws joined by loose pins, with 1 corner-to-corner brace. Is it rigid or wobbly? (a) wobbly (b) rigid
  5. 5.🔺 Which shape keeps its shape best when its corners are pinned? (a) triangle (b) hexagon (c) square (d) rectangle
  6. 6.🔺 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?
  7. 7.🔺 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?
  8. 8.🔺 Which strong shape does a crane arm use? (a) arch (b) beam (c) triangle (d) dome
  9. 9.🔺 A flat frame has 6 straight sides joined by loose pins at the corners. What is the least number of corner-to-corner braces needed to make it rigid?
  10. 10.🔺 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?
  11. 11.Which of these uses a beam? (a) a plank over a drain (b) an old stone bridge (c) a roof truss (d) a fort gateway
  12. 12.🔺 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
  13. 13.🔺 Which strong shape does an electric pylon use? (a) dome (b) beam (c) triangle (d) arch
  14. 14.Which of these uses a dome? (a) a crane arm (b) a fort gateway (c) a roof truss (d) a planetarium roof
  15. 15.🔺 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?
  16. 16.🔺 A beam bends under a load. Its top side is … (a) squeezed (compression) (b) floating (c) not affected (d) stretched (tension)
  17. 17.True or false: a roof truss uses a beam. (a) False (b) True
  18. 18.True or false: an old stone bridge uses a dome. (a) True (b) False
  19. 19.True or false: a truss bridge side uses a dome. (a) False (b) True
  20. 20.Which of these uses a dome? (a) a truss bridge side (b) a round palace roof (c) a plank over a drain (d) a fort gateway
  21. 21.🔺 Which strong shape does a slab over a canal use? (a) arch (b) dome (c) beam (d) triangle
  22. 22.Which of these uses triangles? (a) an old stone bridge (b) a lintel over a door (c) an igloo (d) a crane arm
  23. 23.🔺 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?
  24. 24.🔺 How do engineers stop a square frame from wobbling? (a) paint it (b) make it bigger (c) take off a side (d) add a diagonal brace
  25. 25.Which of these uses triangles? (a) a truss bridge side (b) a fort gateway (c) a slab over a canal (d) a lintel over a door
  26. 26.🔺 Which strong shape does a lintel over a door use? (a) arch (b) dome (c) triangle (d) beam
  27. 27.True or false: an igloo uses a beam. (a) False (b) True
  28. 28.True or false: a shelf on two brackets uses a beam. (a) True (b) False
  29. 29.True or false: an old stone bridge uses an arch. (a) False (b) True
  30. 30.True or false: a roof truss uses a dome. (a) True (b) False
  31. 31.True or false: a bicycle frame uses an arch. (a) False (b) True
  32. 32.True or false: a round palace roof uses an arch. (a) False (b) True
  33. 33.🔺 Which strong shape does an igloo use? (a) dome (b) arch (c) triangle (d) beam
  34. 34.🔺 A flat frame has 12 straight sides joined by loose pins at the corners. What is the least number of corner-to-corner braces needed to make it rigid?
  35. 35.🔺 Which strong shape does a bicycle frame use? (a) arch (b) dome (c) triangle (d) beam
  36. 36.🔺 A frame shaped like a hexagon is made of straws joined by loose pins, with 0 corner-to-corner braces. Is it rigid or wobbly? (a) wobbly (b) rigid
  37. 37.Which of these uses triangles? (a) a slab over a canal (b) a roof truss (c) a plank over a drain (d) a lintel over a door
  38. 38.🔺 Which strong shape does a shelf on two brackets use? (a) arch (b) beam (c) dome (d) triangle
  39. 39.🔺 Which strong shape does a truss bridge side use? (a) dome (b) triangle (c) beam (d) arch
  40. 40.True or false: a slab over a canal uses triangles. (a) False (b) True

Answer key

  1. beam
  2. it works in compression
  3. 27
  4. wobbly
  5. triangle
  6. 3
  7. 8
  8. triangle
  9. 3
  10. 23
  11. a plank over a drain
  12. rigid
  13. triangle
  14. a planetarium roof
  15. 1
  16. squeezed (compression)
  17. False
  18. False
  19. False
  20. a round palace roof
  21. beam
  22. a crane arm
  23. 5
  24. add a diagonal brace
  25. a truss bridge side
  26. beam
  27. False
  28. True
  29. True
  30. False
  31. False
  32. False
  33. dome
  34. 9
  35. triangle
  36. wobbly
  37. a roof truss
  38. beam
  39. triangle
  40. False

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