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ASSESSERING

  • Lys die stowwe waaruit die volgende voorwerpe hoofsaaklik bestaan en dui aan of dit magneties (M) of nie-magneties (NM) is:
Voorwerp Stof waaruit dit bestaan Magneties / nie-magneties
R2-stuk
Skuifspeld
Vuurhoutjie
Brood
Motor
Skeermeslemmetjie
Potlood
R50-noot
Kosblik
Skoolhemp
Trui
Mieliepap
Mes
Skoen
Sakdoek
SELFASSESSERING
1 2 3 4
Alles korrek
Slegs twee verkeerd
Vyf verkeerd
Minder as vyf korrek

3. MATERIALE KAN ROES

Wanneer yster of staal stelselmatig afgetakel word, word dit roes genoem. Roes is ‘n vorm van korrosie.

In die drie of vier sekondes wat dit jou neem om ‘n sin te

lees, verloor Brittanje 40 kg yster of staal.

Die rede:

Dit het verander in roes. Veertig kilogram

yster is genoeg om vier fietse van te maak.

Dit is m.a.w. ‘n chemiese reaksie. Wanneer ‘n metaal roes, verander dit na ‘n nuwe stof. Dit is moeilik om dit weer terug te verander na wat dit was. Die metaal verloor sy glans en kan selfs breek.

Metale (yster en staal) roes makliker wanneer dit nat is of wanneer dit buitekant in nat weer gelaat word. Wanneer metale naby soutwater gelaat word, roes dit selfs nog makliker.

Wanneer yster roes, reageer dit met suurstof en vorm ‘n bruin ysteroksied:

yster + suurstof = bruin ysteroksied

ysteroksied + water = roes

Yster sal net roes as dit aan

suurstof en water

blootgestel word.

Alhoewel yster en staal makliker roes as ander metale, word staal gebruik om skepe, motors, brûe en ander strukture te bou, want dit is goedkoper en sterker as ander boumateriale.

Roes kos maatskappye miljoene rande, want yster- en staalvoorwerpe moet beskerm word teen roes en dit wat reeds geroes het, moet vervang word.

OPDRAG 3

  • Doen die volgende eksperiment om vas te stel wanneer roes plaasvind. Stel 7 proefbuise op (soos aangedui):

  • Bekyk die proefbuise na 4 dae en skryf jou waarnemings in die tabel hieronder neer:
WAARNEMINGS
Proefbuis 1 ___________________________________________
Proefbuis 2 ___________________________________________
Proefbuis 3 ___________________________________________
Proefbuis 4 ___________________________________________
Proefbuis 5 ___________________________________________
Proefbuis 6 ___________________________________________
Proefbuis 7 ___________________________________________

Gevolgtrekking: _______________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

ASSESSERING

Gebruik nou die kennis wat jy opgedoen het en maak die volgende afleidings:

1. Hoekom is daar ‘n lagie olie bo-op die water in proefbuis 2?

_____________________________________________________________________

_____________________________________________________________________

2. Die spykers in proefbuise 1 en 3 roes wel. Hoekom?

_____________________________________________________________________

_____________________________________________________________________

3. Hoekom het proefbuis 5 ‘n rubberprop op?

_____________________________________________________________________

Questions & Answers

A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
Aislinn Reply
cm
tijani
what is titration
John Reply
what is physics
Siyaka Reply
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Jude Reply
Can you compute that for me. Ty
Jude
what is the dimension formula of energy?
David Reply
what is viscosity?
David
what is inorganic
emma Reply
what is chemistry
Youesf Reply
what is inorganic
emma
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
Krampah Reply
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
Sahid Reply
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
Samuel Reply
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Joseph Reply
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
Ryan
what's motion
Maurice Reply
what are the types of wave
Maurice
answer
Magreth
progressive wave
Magreth
hello friend how are you
Muhammad Reply
fine, how about you?
Mohammed
hi
Mujahid
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
yasuo Reply
Who can show me the full solution in this problem?
Reofrir Reply
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Source:  OpenStax, Natuurwetenskappe graad 6. OpenStax CNX. Sep 17, 2009 Download for free at http://cnx.org/content/col11080/1.1
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