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Mechanical energy - Contenido educativo

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Subido el 5 de mayo de 2020 por Segismundo P.

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hi guys I would like to explain you what is energy and the things that you have 00:00:00
to know this year about energy okay so energy we could say that energy is the 00:00:08
ability to produce a change so we say in our everyday life that we feel very 00:00:16
energetic when we have energy when we can do things so we will say that energy 00:00:24
is the ability to produce a change and as any other physical magnitude we have 00:00:31
to be able to measure energy and to use a unit so it's a physical magnitude 00:00:37
physical magnitude and as any other physical magnitude it has a unit okay 00:00:45
that in the international system the unit is the joule okay and we write it as a big J or an 00:01:01
uppercase J okay there are different types of energy for example light energy thermal energy 00:01:10
light energy that we receive from the sun or from a light bulb and thermal energy that we also 00:01:20
reside from the sun or maybe from a heater okay and we also have sound energy that is produced by 00:01:26
a loudspeaker so that there are different types of energy and we can transfer the energy from one 00:01:37
body to another or transform the energy from one type of energy to a different type of energy so we 00:01:45
have energy of type 1 imagine for example light energy or luminous energy 00:01:52
and we can transform this energy in other type of energy for example heat or 00:02:03
thermal energy okay so in this transformation the energy is constant so 00:02:21
So the amount of joules that we have here is the same than the amount of joules that 00:02:30
we have here. 00:02:36
So energy can be transformed or transferred but it remains constant and this is a conservation 00:02:37
law which says that energy is constant. 00:03:16
can transform it we can transfer it energy cannot be created neither created 00:03:19
nor destroyed okay so can be only transformed or transferred for example 00:03:27
if there is a ball on the ground and I kick the ball part of the energy of my 00:03:34
muscles are transferred to the ball that will start moving and when you have 00:03:39
motion that's mechanical energy okay so the next thing that I want you to 00:03:44
know is that one of the most important types of energy we are going to learn in 00:03:50
physics is energy due to position or speed position it means the height okay 00:03:57
so and the energy that is related with position will be called a potential 00:04:20
energy and the energy related to the speed will be called kinetic energy and 00:04:28
if we add these two energies together what we obtain is the mechanical energy 00:04:44
so this plus this is mechanical energy so we can say that mechanical energy 00:04:53
this is mechanical equals potential energy plus kinetic energy potential 00:05:03
energy plus kinetic energy okay and we are going to learn now what is the 00:05:25
equation that is going to enable us to calculate the energy for kinetic and for 00:05:48
potential energy okay I would like to highlight in some way this equation and 00:05:55
then potential energy this one potential energy as I told you it depends on the 00:06:09
height but it also depends on the mass and on the gravity so it's 00:06:20
going to be the mass times the acceleration of the gravity times the 00:06:26
height so M is the mass and we measure it in kilograms so we should add the 00:06:30
mass in kilograms in this equation G is the acceleration of the gravity and on 00:06:39
the surface of the earth is 9.8 meters per second square and finally H is the 00:06:48
height and we measure this in meters okay this m is mass and this m is 00:06:56
meters so please don't confuse them okay so this is the equation for potential 00:07:08
energy so you see that the more mass has an object the more the energy that it 00:07:16
has and the tallest or the highest the higher that is an object the more 00:07:22
energetic it's going to be and then we can express potential kinetic sorry 00:07:28
kinetic energy as one half times the mass times the speed squared okay and we 00:07:38
can use this second equation to calculate the kinetic energy M is the 00:07:52
mass and V is the speed and we measure the speed in meters per second okay let's 00:07:58
try to solve an example to illustrate this okay so imagine that we have this 00:08:13
is an example imagine that we have a lorry okay so imagine that there is a 00:08:21
bridge and here is the ground round level there is a bridge imagine there is 00:08:30
a bridge and there is a lorry crossing through the bridge and you imagine that 00:08:43
the mass of the lorry is 10,000 kilograms okay and the lorry is moving 00:08:50
at the speed of 25 meters per second okay and this bridge imagine that is 10 00:09:01
meters tall okay and we want to calculate the kinetic energy the 00:09:18
potential energy and the mechanical energy okay this is what I want you to 00:09:27
calculate so let's start let's start with the kinetic energy it's going to be 00:09:34
one half times the mass times the speed squared so this is one half the mass is 00:09:41
10,000 and the speed squared is 25 squared as we are writing everything in 00:09:51
international system units we will obtain the result in joules okay so I 00:10:02
have to find my calculator here this and this is 25 squared times 7,000 over 2 00:10:09
and this is three million one hundred and twenty five thousand joules okay 00:10:23
then the second thing that we need to calculate is the potential energy that 00:10:36
equals M times G times H okay and this is going to be M is ten thousand again 00:10:41
in kilograms, g is 9.8 and the height is 10 and if you calculate that is 980,000 00:10:53
joules and then finally the mechanical energy is the kinetic plus the potential 00:11:15
so it's 3,125,000 plus 980,000, so if we calculate that, this is 4,105,000 euros, 00:11:24
okay, and this is the third thing, or the third noun we have to calculate, 00:11:53
so this is the energy that something has just by the fact of being moving and not being on the 00:12:02
ground being elevated okay so when you see this video you could do the homework that i have 00:12:12
proposed and that's all for now okay i hope you continue being well i'll see you soon bye 00:12:21
Idioma/s:
en
Autor/es:
Segismundo Peláez Lirola
Subido por:
Segismundo P.
Licencia:
Reconocimiento - No comercial - Compartir igual
Visualizaciones:
107
Fecha:
5 de mayo de 2020 - 13:02
Visibilidad:
Público
Duración:
12′ 36″
Relación de aspecto:
1.78:1
Resolución:
1364x768 píxeles
Tamaño:
18.50 MBytes

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