Om eenvoudige probleme op te los deur vergelykings te vorm
Aktiwiteit 1
Om eenvoudige probleme te doen deur vergelykings te vorm en op te los
[lu 2.2, 2.4]
Hoe word hierdie probleem gedoen?
Jamie se pa is vier keer so oud as Jamie. Sy pa is 40; hoe oud is Jamie?
a) Miskien moet ons baie hard dink en ‘n paar raaiskote waag, soos: As Jamie 1 is, is sy pa 4. Nie reg nie. Wat van 2 jaar oud? Ensovoorts.
b) Maak ‘n tabel en voltooi die spasies. Help dit?
Ouderdom
1
2
3
4
Ouderdom х 4
4
8
12
28
40
c) Teken ‘n vloeidiagram. Help dit?
Daar is duidelik nie veel verskil tussen die drie metodes nie – jy kan enigeen gebruik wat jou pas. Hulle is egter nie van veel waarde nie, want jy moet nog so baie raai. Vir moeiliker probleme word hierdie metodes onmoontlik om te gebruik.
Gelukkig is daar ‘n beter manier.
Die beste metode om hierdie probleem aan te pak is om ‘n vergelyking vanuit die inligting te vorm. Dan los ons die vergelyking op en skryf die antwoord neer uit die oplossing van die vergelyking.
Dis moeilik om vergelykings te vorm, maar dit word makliker met oefening.
Vir ‘n vergelyking benodig ons ‘n gelykaanteken en ‘n veranderlike (ons gebruik dikwels
x , maar dit kan enige letter wees).
Jamie se pa is vier keer so oud as Jamie. Sy pa is 40; hoe oud is Jamie?
In die algemeen lyk die vergelyking so:
Vier maal Jamie se ouderdom = vader se ouderdom wat 40 is.
Die vraag vereis Jamie se ouderdom; dus:
Laat Jamie se ouderdomxwees .
Nou word die vergelyking: 4
x = 40
Ons moet ‘n getal vind wat 40 gee as ons dit met 4 vermenigvuldig. As ons 40 deur 4 deel, is die antwoord 10. Dus moet
х 10 wees, en Jamie is dus 10 jaar oud. Dis maklik om te bevestig dat dit die korrekte antwoord is.
‘n Probleem vir jou:
Leon het 48 albasters. Amy het slegs ‘n derde soveel as Leon; hoeveel het sy? Gebruik die vorige metode.
Sit jou antwoord op hierdie manier uiteen:
Wat stel die veranderlike voor?.
Skryf ‘n vergelyking met hierdie veranderlike.
Los die vergelyking op.
Skryf die oplossing neer, m.a.w. wat die waarde van die veranderlike is.
Skryf die antwoord op die probleem in woorde neer.
Let op dat die eerste stap en laaste stap in woorde is, en die middelste stappe, algebra.
Oefening:
Vind die antwoorde op die volgende probleme:
1. Mnr. Jacobs het R295,45 in sy sak. Mev. Jacobs het R55,30 minder as haar man in haar handsak. Wat is die bedrag in haar handsak?
2. Ek dink aan ‘n getal. Ek vermenigvuldig dit met 7 en deel die antwoord deur 3. Die resultaat is 49. Wat is die getal waaraan ek gedink het? Onthou om jou antwoord te kontroleer.
3. In Amerika koop Joanie ‘n item wat $5,75 kos. Sy bereken dat dit R41,69 is as sy dollars na rande omskakel. Wat is die dollar–rand wisselkoers wat sy gebruik het?
Aktiwiteit 2
Om doeltreffende metodes te ontwikkel vir moeiliker probleme
[lu 2.3, 2.4]
Ons gaan nog woordsomme doen, maar ons gaan eers op die algebra in die oplossing konsentreer. Maak telkens seker dat jy weet wat elke stap beteken, en waarom dit gedoen word.
Party van die volgende probleme word deur hul oplossings gevolg. Probeer eers om self by die antwoord uit te kom voor jy verder lees. Vergelyk dan jou antwoord en die manier waarop jy dit uiteensit.
Questions & Answers
Three charges q_{1}=+3\mu C, q_{2}=+6\mu C and q_{3}=+8\mu C are located at (2,0)m (0,0)m and (0,3) coordinates respectively. Find the magnitude and direction acted upon q_{2} by the two other charges.Draw the correct graphical illustration of the problem above showing the direction of all forces.
To solve this problem, we need to first find the net force acting on charge q_{2}. The magnitude of the force exerted by q_{1} on q_{2} is given by F=\frac{kq_{1}q_{2}}{r^{2}} where k is the Coulomb constant, q_{1} and q_{2} are the charges of the particles, and r is the distance between them.
Muhammed
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Capacitor is a separation of opposite charges using an insulator of very small dimension between them. Capacitor is used for allowing an AC (alternating current) to pass while a DC (direct current) is blocked.
Gautam
A motor travelling at 72km/m on sighting a stop sign applying the breaks such that under constant deaccelerate in the meters of 50 metres what is the magnitude of the accelerate
velocity can be 72 km/h in question. 72 km/h=20 m/s, v^2=2.a.x , 20^2=2.a.50, a=4 m/s^2.
Mehmet
A boat travels due east at a speed of 40meter per seconds across a river flowing due south at 30meter per seconds. what is the resultant speed of the boat
which has a higher temperature, 1cup of boiling water or 1teapot of boiling water which can transfer more heat 1cup of boiling water or 1 teapot of boiling water explain your . answer
I believe temperature being an intensive property does not change for any amount of boiling water whereas heat being an extensive property changes with amount/size of the system.
Someone
Scratch that
Someone
temperature for any amount of water to boil at ntp is 100⁰C (it is a state function and and intensive property) and it depends both will give same amount of heat because the surface available for heat transfer is greater in case of the kettle as well as the heat stored in it but if you talk.....
Someone
about the amount of heat stored in the system then in that case since the mass of water in the kettle is greater so more energy is required to raise the temperature b/c more molecules of water are present in the kettle
pratica A on solution of hydro chloric acid,B is a solution containing 0.5000 mole ofsodium chlorid per dm³,put A in the burret and titrate 20.00 or 25.00cm³ portion of B using melting orange as the indicator. record the deside of your burret tabulate the burret reading and calculate the average volume of acid used?
No. According to Isac Newtons law. this two bodies maybe you and the wall beside you.
Attracting depends on the mass och each body and distance between them.
Dlovan
Are you really asking if two bodies have to be charged to be influenced by Coulombs Law?
Specific heat capacity is a measure of the amount of energy required to raise the temperature of a substance by one degree Celsius (or Kelvin). It is measured in Joules per kilogram per degree Celsius (J/kg°C).
AI-Robot
specific heat capacity is the amount of energy needed to raise the temperature of a substance by one degree Celsius or kelvin
ROKEEB
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