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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

show that the set of all natural number form semi group under the composition of addition
Nikhil Reply
what is the meaning
Dominic
explain and give four Example hyperbolic function
Lukman Reply
_3_2_1
felecia
⅗ ⅔½
felecia
_½+⅔-¾
felecia
The denominator of a certain fraction is 9 more than the numerator. If 6 is added to both terms of the fraction, the value of the fraction becomes 2/3. Find the original fraction. 2. The sum of the least and greatest of 3 consecutive integers is 60. What are the valu
SABAL Reply
1. x + 6 2 -------------- = _ x + 9 + 6 3 x + 6 3 ----------- x -- (cross multiply) x + 15 2 3(x + 6) = 2(x + 15) 3x + 18 = 2x + 30 (-2x from both) x + 18 = 30 (-18 from both) x = 12 Test: 12 + 6 18 2 -------------- = --- = --- 12 + 9 + 6 27 3
Pawel
2. (x) + (x + 2) = 60 2x + 2 = 60 2x = 58 x = 29 29, 30, & 31
Pawel
ok
Ifeanyi
on number 2 question How did you got 2x +2
Ifeanyi
combine like terms. x + x + 2 is same as 2x + 2
Pawel
x*x=2
felecia
2+2x=
felecia
×/×+9+6/1
Debbie
Q2 x+(x+2)+(x+4)=60 3x+6=60 3x+6-6=60-6 3x=54 3x/3=54/3 x=18 :. The numbers are 18,20 and 22
Naagmenkoma
Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?
mariel Reply
Mark = x,. Don = 3x + 1 x + 3x + 1 = 113 4x = 112, x = 28 Mark = 28, Don = 85, 28 + 85 = 113
Pawel
how do I set up the problem?
Harshika Reply
what is a solution set?
Harshika
find the subring of gaussian integers?
Rofiqul
hello, I am happy to help!
Shirley Reply
please can go further on polynomials quadratic
Abdullahi
hi mam
Mark
I need quadratic equation link to Alpa Beta
Abdullahi Reply
find the value of 2x=32
Felix Reply
divide by 2 on each side of the equal sign to solve for x
corri
X=16
Michael
Want to review on complex number 1.What are complex number 2.How to solve complex number problems.
Beyan
yes i wantt to review
Mark
16
Makan
x=16
Makan
use the y -intercept and slope to sketch the graph of the equation y=6x
Only Reply
how do we prove the quadratic formular
Seidu Reply
please help me prove quadratic formula
Darius
hello, if you have a question about Algebra 2. I may be able to help. I am an Algebra 2 Teacher
Shirley Reply
thank you help me with how to prove the quadratic equation
Seidu
may God blessed u for that. Please I want u to help me in sets.
Opoku
what is math number
Tric Reply
4
Trista
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
Sidiki Reply
can you teacch how to solve that🙏
Mark
Solve for the first variable in one of the equations, then substitute the result into the other equation. Point For: (6111,4111,−411)(6111,4111,-411) Equation Form: x=6111,y=4111,z=−411x=6111,y=4111,z=-411
Brenna
(61/11,41/11,−4/11)
Brenna
x=61/11 y=41/11 z=−4/11 x=61/11 y=41/11 z=-4/11
Brenna
Need help solving this problem (2/7)^-2
Simone Reply
x+2y-z=7
Sidiki
what is the coefficient of -4×
Mehri Reply
-1
Shedrak
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Kimberly Reply
Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
August Reply
What is the expressiin for seven less than four times the number of nickels
Leonardo Reply
How do i figure this problem out.
how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
Shanjida
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
s.
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
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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