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Algebra and Arrays - Contenido educativo

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Subido el 28 de mayo de 2007 por EducaMadrid

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NASA Connect segment exploring how algebra and arrays are used in NASA's activities. The segment also explains voltage, current, amp, and resistance.

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How is algebra used to find a solution? 00:00:00
How are arrays used in algebra? 00:00:05
What algebraic equation shows that voltage is related to current? 00:00:08
Hey guys, meet Leslie Curtis. She's an engineer here at NASA Marshall. 00:00:14
Thanks, Van. Dr. Gilchrist is right. 00:00:18
Mathematics is one of the most powerful tools that we have available to us at NASA. 00:00:21
We use algebra almost every day to find solutions to our problems. 00:00:25
This is the Icarus satellite that Jane told us about. 00:00:29
It uses solar cells to charge its batteries. 00:00:32
Solar cells, which convert sunlight into electricity, are arranged in a pattern called an array. 00:00:35
One of the ways that equations can be written in algebra is also called an array or matrix. 00:00:41
Actually, they look a lot alike. Let's compare them. 00:00:47
Here's an example of an array used in algebra. Notice the pattern of rows and columns. 00:00:51
Now here's a picture of a solar array. See the rows and columns again? 00:00:57
Let's use the solar arrays on the Icarus satellite to do a simple math problem that the students at the University of Michigan were faced with. 00:01:02
Then let's compare solar arrays with algebraic arrays. 00:01:10
The Icarus satellite uses 12-volt batteries. Voltage is a measurement of electricity. 00:01:13
And if we use a solar array to charge our batteries, we know from science that we need to have a solar array voltage 00:01:19
that is slightly higher than the 12-volt batteries, so let's say 15 volts. 00:01:24
To calculate the number of solar cells we need for the array, we use algebra. 00:01:29
And since each Icarus solar cell provides 0.5 or a half a volt of charge, 00:01:34
how many cells do we need for our solar array to produce the 15 volts? 00:01:40
If we solve for C, which stands for the number of cells, 00:01:44
we see that it will take 30 cells to give us 15 volts to successfully charge the batteries. 00:01:47
From this information, we can arrange our solar cells in a solar array pattern. 00:01:53
Cool! Like 10 cells wide by 3 cells high? 00:01:58
Or 15 cells wide by 2 cells high. 00:02:01
So you see, when scientists are trying to calculate complicated equations, 00:02:04
we often write them in the pattern of an algebraic array. 00:02:08
That's great! So you use patterns and algebra to determine the amount of solar cells in an array. 00:02:11
But let me ask you this. How long does it take for solar cells to charge Icarus's batteries? 00:02:17
Well, that question can be answered using algebra also. 00:02:24
We know that the charge on the Icarus satellite batteries is related to current and time. 00:02:27
Current is another measure of electricity, which is expressed in units called amperes, or amps for short. 00:02:32
Now, to calculate the amount of time needed to charge the batteries, we use the following equation. 00:02:38
Charge is equal to current times time. 00:02:44
Since we want to know the length of time needed to charge the batteries, 00:02:47
we can rewrite the equation as time is equal to charge divided by current. 00:02:51
The Icarus satellite batteries have a maximum charge capacity of 2.5 amp hours. 00:02:56
A typical charging current that we might use to charge the system is 0.5 amps. 00:03:02
So if the charge is 2.5 amp hours and the current is 0.5 amps, the equation can be written this way. 00:03:08
Time is equal to 2.5 amp hours divided by 0.5 amps. 00:03:16
Solving for time, we can see that the time required to reach full charge on the system is 5 hours. 00:03:22
Okay, let me see if I got this straight. 00:03:29
We use voltage as a way of measuring electricity when we're talking about the solar array, 00:03:31
and current to describe electricity when we're calculating the time it takes to recharge the batteries. 00:03:36
But how are voltage and current related? 00:03:43
Voltage and current are related by the simple equation V equals IR. 00:03:46
V stands for voltage, which is usually measured in volts. 00:03:51
I is the current, which is usually measured in amps. 00:03:55
And R is called the resistance. 00:03:58
The resistance is measured in units called ohms. 00:04:00
And the equation V equals IR is actually called Ohm's Law after G.S. Ohm, a German scientist. 00:04:03
And the unit of resistance was named in his honor. 00:04:10
You just wouldn't believe the resistance I got. 00:04:13
Shocking. 00:04:17
You know, I think it's pretty sweet that the university students used algebra to work with NASA on the ProSense experiment. 00:04:19
But I don't really get the volts and amps and resistance. 00:04:26
Oh my. 00:04:31
Volts and amps and resistance. 00:04:32
Oh my. 00:04:34
I get it, Dorothy. 00:04:35
I get it. 00:04:36
I just couldn't resist. 00:04:37
Nor could we resist the chance to meet some students who teamed up with NASA Connect and are wired for today's web activity. 00:04:39
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Idioma/s:
en
Materias:
Matemáticas
Niveles educativos:
▼ Mostrar / ocultar niveles
      • Nivel Intermedio
Autor/es:
NASA LaRC Office of Education
Subido por:
EducaMadrid
Licencia:
Reconocimiento - No comercial - Sin obra derivada
Visualizaciones:
431
Fecha:
28 de mayo de 2007 - 16:53
Visibilidad:
Público
Enlace Relacionado:
NASAs center for distance learning
Duración:
04′ 50″
Relación de aspecto:
4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.
Resolución:
480x360 píxeles
Tamaño:
29.12 MBytes

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