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Technology

Grade 8

Structures

Module 5

Beams, pillars, struts, crossbars and anchoring lines

Activity 1

Beams, pillars, supports/struts, crossbars and anchoring lines:

  • The above are important parts of structures. They are used in buildings, bridges and other objects. The pipes forming the framework of your bicycle, for instance, belong to the category of beams.
  • The main function of beams is to bear a load. If the load is too heavy, the beams will bend. In the past, tree trunks were used to provide solid beams, but the cost and weight of these have necessitated the development of different forms of structures, made from a variety of materials, used as beams.

  • Pillars and lampposts are beams that are used vertically. Pillars are useful in buildings for supporting overhanging verandas. If the pillars do not have the capacity to bear the load, the building will collapse. We now and again read about buildings, e.g. shopping centres that collapse.
  • Brackets of some or other type are sometimes used to mount TV sets against walls. It will be clear to you that the TV set causes stress to the platform on which it rests, which actually can be classed as a beam. Being supported at one end only, such a beam is called a crossbeam. To keep the crossbeam in position, a strut is used as support.
  • Similar struts are used in tents and for power lines. In such cases, the struts may be cables and ropes.

  • This sketch shows how a learner reinforced his bridge (a beam) made of drinking straws, by means of a strut and string.

Assignment 1

  • Examine the following illustrations and describe the ways in which technology was used to solve problems occurring in different cultures.

Assignment 2

  • Refer to the following and describe the impact that technological development with regard to structures has had on the lifestyle of people.
  • Skyscrapers
  • Aeroplanes
  • Roof trusses
  • Railway lines and trains
  • Bridges
LO 3.2

Assessment

LO 3
TECHNOLOGY, SOCIETY AND THE ENVIRONMENT The learner will be able to demonstrate an understanding of the interrelationships between science, technology and the environment.
This is demonstrated when the learner:
indigenous Technology and Culture:3.1 compares how different cultures have solved similar problems and relates the differences to the culture and values of their societies;
impact of Technology:3.2 expresses and details opinions about the positive and negative impacts of products of Technology on the quality of people’s lives and the environment in which they live.

Memorandum

ACTIVITY 1

Allow learners to discuss beams, pillars, struts, crossbeams and anchor lines and to list examples. Let them explain where the stresses are exerted and what the application of a specific structure is, why it is suitable for the application and how it could be improved. In the case of a crossbar, the stress, for instance, is exerted below; a pillar bears vertical stress that is equally strong all over.

Assignment 1

  • It is important to use correct terminology when discussing examples:
  • Bow and arrow :Problem: It was necessary to hunt to get food. Animals could not be caught by hand. It became necessary to design a weapon.The bow and arrow as a structure: The string is used to exert the force of stress on the bow. The bending of the bow makes it possible to transfer this force to the arrow as the force of compression. The arrow, as a beam, causes the force to work in the direction of the arrow point to penetrate the prey.
  • CrossbowLike the bow and arrow, but more accurate and more powerful.
  • Shield and spearThe spear serves as a beam, which means that the force is exerted in the direction of the point, which can therefore penetrate the prey. The shield forms a shell structure, with the skin as shell and the wood as a frame.
  • SwordThe blade works as a beam.
  • Ordinary hutA shell structure, with the woodwork as frame and the grass as shell.
  • Rondavel and thatch-roofed housesLike ordinary huts, but with the clay forming part of the shell.

Assignment 2

  • Skyscrapers : larger numbers of people are able to inhabit a specific space. This facilitates urbanisation and makes demands on urban transport, sewerage, electricity supply, removal of storm water: problems that had to be solved by means of technology and have created job opportunities, which lead to further urbanisation.
  • Aeroplanes : great distances can be covered in brief periods of time, which means that both people and goods can be transported quickly. This, however, has implications with regard to pollution and the utilisation of natural resources. It also increases the tempo of living.
  • Roof trusses : For people who live in inhospitable climatic regions, roof trusses prevent roofs from collapsing when there are heavy snowfalls and hail.
  • Railway lines and trains : As with aeroplanes, but trains have also enabled people to spread civilisation across the globe.
  • Bridges : as with aeroplanes and trains.

Questions & Answers

can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
Commplementary angles
Idrissa Reply
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
yes
Asali
I'm not good at math so would you help me
Samantha
what is the problem that i will help you to self with?
Asali
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Technology grade 8. OpenStax CNX. Sep 13, 2009 Download for free at http://cnx.org/content/col11052/1.1
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