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Ejercicio 11 p125

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Subido el 18 de marzo de 2020 por Segismundo P.

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hi guys I have received some questions from you asking how to solve the 00:00:03
exercises from unit 5 so this video is to help you to understand how to do that 00:00:10
okay we will start with exercises 11 and 12 from page 125 to do that I remind you 00:00:16
that definition of average speed the average speed is the distance traveled 00:00:27
divided by the time taken and the definition of acceleration. The acceleration is the speed 00:00:31
variation and you know that we write this with the delta letter from the Greek alphabet divided 00:00:38
by the time taken. Okay so we will start with exercise 11. I'm going to change this to a kind of 00:00:44
board to write things on it. Just one second please because I'm also trying to get used to 00:00:50
this way of teaching so okay so exercise number 11 the welding says what variation in speed is 00:00:58
produced during motion if acceleration is minus 2.5 meters per second square for six seconds 00:01:08
so i remind you that we are on exercise 11 okay let me check just if okay that's all good okay 00:01:15
sorry for the interruption and this exercise is on page 125 right so we have 00:01:28
the data we have for this exercise is that the acceleration is minus 2.5 00:01:36
meters per second squared okay as you can see is a negative acceleration so 00:01:43
that means that the speed is going to decrease okay we are in some way 00:01:49
breaking okay and we are applying this acceleration for six seconds so the 00:01:55
variation in time is six seconds that's the data we have and the unknown that is 00:02:03
being asked unknown is the variation in speed so what is the variation in speed 00:02:10
that's the unknown. What equation we are going to use? Well, the equation we are going to use 00:02:20
is that the acceleration equals the variation in speed over the variation in time. So we are going 00:02:28
to solve, try to solve this. So we, as usual, we have an equation and we have different variables 00:02:36
and we know all of them but one and that one that we don't know is the unknown so 00:02:45
we have to solve for Delta V and if we solve for Delta V we isolate Delta V so 00:02:50
Delta T will pass to this side multiplying so Delta V equals a times 00:02:56
Delta T okay and now next step we have to be careful is the units do we have 00:03:03
the proper units yes we do so we can continue solving so we write the 00:03:13
acceleration is minus 2.5 meters per second square multiplied by the time 00:03:19
that is 6 seconds as you see we can cancel this second with the square and 00:03:26
we finally have meters per second which are units of our units of velocity and 00:03:31
Now, if you, I'm taking my calculator, 00:03:40
if you do that, you will get a result of 15, 00:03:45
or minus 15 meters per second. 00:03:49
So that's the variation in speed, 00:03:54
is minus 15 meters per second. 00:03:56
And that's the result, okay? 00:04:00
So the point is that you try to do these exercises, 00:04:02
you write them in your notebook, 00:04:07
and later on I will create a task for you to send me with a picture or with a 00:04:09
scanner or whatever the way is possible for you send me the feedback on the 00:04:17
things that you are working I will correct them so those that are 00:04:23
correcting in videos you can upload the correction okay the point is that as the 00:04:28
platform is not working smoothly yet you will have time to do that so don't get 00:04:33
stressed continue working but don't worry okay so I hope to see you soon 00:04:40
later and I will upload a second video for the 12th because I don't want to 00:04:46
make a heavy or too large video for the platform okay so see you soon bye 00:04:51
Idioma/s:
es
Autor/es:
Segismundo Peláez
Subido por:
Segismundo P.
Licencia:
Reconocimiento - No comercial - Compartir igual
Visualizaciones:
105
Fecha:
18 de marzo de 2020 - 13:15
Visibilidad:
Público
Duración:
05′ 01″
Relación de aspecto:
1.78:1
Resolución:
1364x768 píxeles
Tamaño:
7.55 MBytes

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