structures and forces

• explain how frictional forces help structures

  force of friction resists movement by heat to help structures stay tg
• 3 key methods to help structures withstand

  1. distribute the load

  2. direct the force along angled components

  3. shape parts to withstand the specific force
• function


  the purpose; what is the structure supposed to do
• aesthetic definition 


  how does the structure look, doesnt add to the function of the structure
• safety


  structures we build must be safe, must stay strong for a long time
• what is a margin of safety

  builders have to meet a margin of safety ensuring that the building is stable
• types of materials


  composite: made from one or more materials

  layered: layered pieces made to make 1 thing (paper straws= glue+ paper tg). woven and knit: materials that have been woven tg
• environental impact 


  personal choice made by designers to be more enviromentally friendly, cost more
• fixed joint


  a joint that doesnt move

  ex. desk leg to chair
• mobile joint 


  joint that allows structure to have movement

  ex. door to door frame
• what are fasteners


  nails, screws, and rivets that make permanent holes in structure
• what are ties


  thread, string, and rope can also fasten things together
• what are adhesives


  thermosetting glue or rubber cement

  AKA. wet —> dry
• whats the difference between welding and soldering

  welding is melting the pieces together while soldering is putting a piece of metal then melting it
• force 


  a push or pull that causes a structure to move or change shape
• effect of a force depends on

  •magnitude

  •direction

  •location
• mass


  the amount if particles/ matter in something, stays the same
• weight


  force acting on an object, gravity affects weight, measueed in newrons
• levers


  a device and that can change the amount of force needed to move
• braces definition and truss

  truss: structure filled with triangular shapes

  braces: added to the structure to direct forces through solid parts of the structure to the ground
• compression


  squishes/ presses down
• tension


  pulls/ stretches
• shear


  opposite directions being pulled
• torsion


  twist
• bending


  combo of tension and compression
• external force


  force applied to a structure by something else
• internal force


  force that one part of a structure exerts on another, part of the same structure
• cost

  everything must fit the budget
• choosing materials: safety


  all structures must meet a "margin of safety" meaning the structure and materials must be strong
• enviroment impact

  • personal choice
• 3 examples of a natural structure


  egg, tree, flowers, honeycomb, etc
• what is a mass structure

  held in place by weight, pilled up materials, need alot of materials

  ex. mountain
• what is a frame strcuture


  have a skeleton of strong materials that support the weight, use less materias, have to join them
• what is a shell structure

  thin, carefully shaped outer layer, very little material, difficult materials, if not perfect= hard to shape
• centre of gravity within forces 


  a centre of gravity found in the middle of a structure to direct forces and distribute the weight
• arches characteristics


  bridges, strong because forces on the load help spread out weight
• cantilever characteristics


  horizontal board or span supported by very strong columns at the end
• triple beam balance


  measures mass
• spring scale


  measures weight
• which type of beam is the strongest

  “i” or “box” beam