Forces and Structures

Question 1

What is a combination structures

Answer 1

• combination of two or more structures
• house (frame + solid), CN Tower (frame + solid + shell)

Question 2

what is a structure?

Answer 2

• Something made up of one or more parts put together that can support a load
• Every structure has a form and function
• Form = basic shape
• Function = it’s purpose
• Function may be easy to identify, example, a ladder. What is its function?

Question 3

what is a human made structure?

Answer 3

• made by human
• buildings, bridges, cars, house, table

Question 4

What is a natural structure?

Answer 4

• created by nature
• trees, nests, shells, skeletons

Question 5

What is a solid structure?

Answer 5

• Usually solid all the way through
• Formed from one solid piece of material
• Weighs more than a hollow structure
• rocks, bricks, cement poles

Question 6

What is a frame structure?

Answer 6

• A structure made of parts joined together
• The parts are called components
• Use less material that solid structures (makes them lighter)
• coral, spider webs, ladder, bike

Question 7

Types of external forces

Answer 7

• Acts on a structure but is not part of the structure
• gravity, friction, tension

Question 8

Types of internal forces

Answer 8

• One part of a structure acting on another
• Compression, Tension, Torsion, Shear

Question 9

How can you strengthen a structure?

Answer 9

• you can make a structure stronger by adding more shapes onto it
• Adding more triangles into a triangle structure or adding triangles into a rectangular structure.

Question 10

Why is a triangle considered the strongest shape?

Answer 10

• when force is put on a point, all weight/force is distributed between structure

Question 11

What is stability?

Answer 11

• Means being able to stay balanced while you
  experience forces
• A measure of how resistant a structure is to being
  knocked over
• Depends on materials and construction techniques, as
  well as centre of gravity

Question 12

What is centre of gravity and how does it affect stability?

Answer 12

• The point at which a mass is equally balanced in all
  directions
• The location of the centre of gravity helps determine
  how stable a structure is
• the lower the centre of gravity is, the hard it will be to knock over the structure (ex. football players crouch when running so they don’t het knocked over easily)

Question 13

What is structural stress? Give an example

Answer 13

• Books on the middle of a shelf may cause the
  shelf to bend. This is called Structural stress
  -When the books are removed the shelf goes back to it’s original shape.

Question 14

What is structural fatigue? Give an example

Answer 14

• repeated stress over time might crack or warp the
  structure (ex. a book shelf) leading to permanent changes.
• permanent changes are called structural fatigue.

Question 15

What is structural failure? Give an example

Answer 15

• if the structure eventually collapses, then that means that the external forces were too strong
• this is structural failure

Question 16

Why do components fail sometimes?

Answer 16

• Shapes of components sometimes can not withstand
  internal or external forces

Question 17

Compression

Answer 17

• Force that squeezes or presses something together

Question 18

Tension

Answer 18

• A force that stretches apart to expand or lengthen

Question 19

Shear

Answer 19

• Force that pushes in opposite directions

Question 20

Torsion

Answer 20

• the force that twists

Question 21

Structures that contain (examples)

Answer 21

• Retaining wall, mug, shopping bag, nest

Question 22

Structures that support (examples)

Answer 22

• Ladder, spider web, shelf

Question 23

Structures that span a space (examples)

Answer 23

• bridge, docks, boardwalks

Question 24

Structures that protect

Answer 24

• Helmet, bubble wrap, roof, shoes, animal den

Question 25

Structures that make a task easier

Answer 25

• Rake, shovel

Question 26

Shell structure (definition)

Answer 26

• A structure that has a solid outer surfaces and hollow inner area
• Lighter, used for protection
• Egg cartons, food cans and bottles, pipes, and clay pots

Question 27

Frame structure (definition)

Answer 27

• A structure made of parts joined together
• The parts are called components
• Use less material that solid structures (makes them lighter)
• spiderwebs, skeletons, bridges, chairs

Question 28

4 properties when describing forces

Answer 28

Magnitude: Strength of the force
Direction: direction the force is coming from
Plane of application: “Slice the force travels along
Point of application: location where the force meets the structure

Question 29

Combonation structure

Answer 29

• a structure with more than one type of structure (frame, shell, solid)
• house (frame & solid) and CN tower (frame, solid, shell)

Question 30

What is force

Answer 30

• A force is any push or pull
• Act on all structures.
• When being built, structures must be designed and built to withstand forces they will face.
• Understanding forces help people build and design better structures.

Question 31

Universal Design

Answer 31

• Structures that are useful beyond their design
• Ex: Wheelchair ramps and automatic doors were designed for people in wheelchairs
• They are also useful for people using walkers, pushing strollers, and for people carrying heavy objects.

Question 32

What is structural stress? Give an example

Answer 32

• Books on the middle of a shelf may cause the
  shelf to bend. This is called Structural stress
  -When the books are removed the shelf goes back to it’s original shape.

Question 33

Failing for safety: how are some structures designed to fail for safety? Give examples

Answer 33

• some structures are known to be dangourous if they fail, so they are designed to fail
• ex. tempered glass. it is dsigned to break into a million little peices, so that you cant get hurt easily

Question 33

The difference between a static and dynamic load

Answer 33

• a static load stays the same, while a dynamic load will change often
• ex. the weight of a building is a static load, but the weight of the people in it is a dynamic load

Question 34

What is planned failure

Answer 34

• planned failure is when the structure has properties that help prepare and protect from failure

Question 35

Structures that looks aesthetically appealing

Answer 35

• you can do this by using various shapes and colours