Chapter 14-15 Flashcards
(24 cards)
What is mass?
Mass is the amount of matter in a substance, mass is measured using a balance, and the unit for mass is grams
What is Structural Efficiency?
Structural efficiency compares the mass of a structure to the mass of the load it supports. The lighter the structural efficiency the stronger and lighter the design.
What is the formula for structural efficiency?
SE=maximum mass supported
—————————————
mass of structure
What is Weight?
Weight is the force of gravity exerted on a mass
Draw a force Diagram for; 5N to the right
[] —–> 5N
What are External forces?
Forces exerted from the outside of the structure
What are Internal forces?
Forces created inside the structure
What is a live load?
Wind and or weight of things inside the structure
What is a dead load?
The weight of the structure itself excluding the contents inside
What are the 4 internal forces?
- Tension Forces
- Compression Forces
- Shear Forces
- Torsion Forces
What is Tension Forces?
Tension is when both ends are pulled apart example; tuggle war
What is Compression Forces?
Compression Force is the application of power, pressure, or exertion against an object that causes it to become squeezed, squashed, or compacted.
What are Shear Forces?
Shearing forces are unaligned forces pushing one part of a body in one direction, and another part of the body in the opposite direction.
What are Torsion Forces?
Torsion forces are when you twist the ends of a material each end in a different direction.
How do you strengthen structures?
You add ties,braces,and gussets
What are Balance Forces?
The forces are balanced if they are equal in size,opposite in direction, and pointing along the same straight line. Balanced Forces do not change an object’s motion.
What is a counter weight?
Counter weight is a mass that balances another mass
What are half circle arches?
Half circle arches or domes distribute their weight to press straight down on their foundations
What are buttresses?
Buttreses are slanted braces outside a wall that prevents the roof from pushing down the walls outward. The slanted trust line carries the weight along each buttress to the ground
What are Trusses?
Trusses are arches with their ends tied together by a strong beam. The outward force on the support is balanced by the inward tension force tie beam, so the support does not tip.
What is spin stabilization?
Spin stabilization is the principle demonstrated by the gyroscope, is espescially useful for objects that do not rest on a solid foundation. Rotation also stabilizes objects that are supported at one end, such as a twirling figure skater.
What is the center pf gravity?
Centre of gravity is the point at which all the gravitational force of an object may be considered to act
What is the thrust line?
The thrust line is the line that runs downwards from an object’s centre of gravity, through which force is trnsfered
What are the principles of stability?
- Build a firm foundation;find something sold,make a solid layer, spread the load
- Balance forces; balanced forces do not change an objects motion, if the dyructure is not pulled apart under tension, the balanced forces will stabilize it
- Keep lines verticalThe supports can be tipped over, as well as collapsed, by the weight of the structure resting on it.
- Use Rapid Rotation;Spin stabilization is the principle demonstrated by the gyroscope, this principle is usefull for objects that do not rest on a solid foundation
