Topic 3-7 Structures And Forces Flashcards
Mass
The amount of matter in a substance; often measured with a balance
Primary standard
The name given to a small cylinder of metal which the kilogram is based: equivalent to 1 kg
Kilogram
The primary measurement of mass in SI ,equal to 1000g; 1 kg is the primary standard for mass
Balance
Add device to measure mass many balances work by using the force of gravity
Forces
A push or Pull or anything that causes a change in the motion of an object
Newton
The standard unit of force in the system international d’ unites (SI)
Force meter
A scientific device used to measure force also called the spring scale
Gravitational force
The force extruded by gravity on an object measured in Newton the preferred scientific term for the every day term
Force diagram
A drawing that uses arrows to represent the direction and strength of one or more forces
Weight
A force of gravity exerted on a mass
External forces
Stresses that act on a structure from outside it
Internal forces
Is the force that one part of the structure exerts onto another part of the same structure
Deformation
The change to a shape or size of the structure caused by internal forces
Dead load
Something that is a permanent load on a structure
Live load
A non-permanent loan force acting on a structure like a moveable chair
Tension force
Pulling
Two forces acting in opposite directions examples tug-of-war, pulling an elastic band apart
Compression force
Squeezing
crushing a metal material by squeezing it together example eating a burger ,stress ball, walking in your shoes , kicking a soccer ball
Tensile strength
Measures
The largest tension force material cant stand before breaking
Compressive strength
Measures the largest compression on a force the material can stand before losing its shape or breaking into pieces
Example
Water balloon when filled to full it breaks
Shear force
Bend /tear
Bend tear a material by purse pricing different parts in opposite directions
examples wrapping paper taking a pop can tab off
Torsion force
Twisting
Twisting a material by turning that ends in the opposite directions examples opening a jar of peanut butter , ring out a wet cloth
Shear strength
Measure the largest force the martial can stand before ripping apart
Torsion strength
Measures the largest force of the materials can stand it and still spring back into its original shape
Bending force
The bending force when a ruler is bent is a combination of tension and compression forces. Why? then bottom of the ruler is coming together while the top of the ruler is spreading apart
Lever
A lever is a device that can change the amount of force needed to make an object Examples Shovel Teeter totter Crow bar
Fulcrum
A fulcrum is the pivot point of a lever
3 ways a material cant fail
Shear
Compression and shearing one section of land may land over another sections along a weakness crack ex. Rockslide
Blend or buckle
Compression and bending compressive forces cause materials to bend ex. Squishing a pice of paper or crunching a can
Torsion
Torsion and shearing. Often materials will shear (break) when they are twisted ex. Twisting dry spaghetti and plastic cutlery
Shear
Ripping paper
Tare
Blend and or buckle
Carpet is compressing bending and it leaves the material deformed
The baseball compresses the glass and causes it to break
A five dollar bill gets squished in your pocket
Torsion
Ur ankle twists when u sprain it
Twisting the lid back and forth causes it to break off
3 design types
Distribute the load throughout the structure
Direct the forces along angled components
Shapes the parts to withstand the specific type of force they are likely to experience
Arch
Keystone: located in the middle at the top of the arch acts like a wedge directs the forces along the stones and down to the ground
Cantilever
A cantilever is a horizontal beam supported at one end by a very strong column which acts like a support to help carry the load on the beam
Ex. Diving board
Viewpoint in South Africa
Brace
braces are added materials angled to direct forces thorough the solid part of the structure
Ex. Sawhorse
Beams
Support attached to the columns that push upwards along with structure
Friction
A force that resists movement between two surfaces that rub together
Stable
Stable means that a structure is less likely to tip over
Centre of gravity
Centre of gravity is when the point at which gravity seems to act on an object or mass. It’s important because it helps us determine how to make something stable and how it will help us with designing a structure
Why is it important to have a firm Foundation
It allows the structure to have a good solid base when building. If you are adding extra weight the foundational be able to support us
Pillings
Pillings are large cylinder structures that are used to carry the weight of structure to hold a solid foundation meant material
example bedrock
Footing
Footings are bases for walls of the foundation of a structure. A footing is wider than the wall to spread the weight over a large area
Gyroscope
Giroscope is a cylinder device with the heavy outer rim that spends at a very fast rate stabilizing the access so that the access always pointing the same direction
Spin stabilization
Spend stabilization essentially means that the faster an object turns the more stable it will be
