Energía MECÁNICA 🎢 Principio de Conservación de la Energía
Summary
TLDREn este video, Susi explica qué es la energía mecánica y cómo calcularla, destacando la suma de la energía potencial y cinética. Presenta ejemplos prácticos como el lanzamiento de una bola por una rampa y cómo se conserva la energía a lo largo del movimiento, mostrando la transformación de la energía potencial en cinética. Además, realiza un ejercicio sobre una caña lanzada al aire, calculando su energía mecánica, cinética y potencial en diferentes puntos, y encontrando su altura máxima. Al final, invita a los espectadores a suscribirse para más contenido educativo.
Takeaways
- 📚 La energía mecánica es la suma de la energía potencial y la energía cinética.
- ⚙️ La fórmula para la energía potencial es masa por gravedad por altura, y para la energía cinética es medio por masa por velocidad al cuadrado.
- 🎢 En una situación sin fricción, la energía mecánica se mantiene constante durante todo el movimiento de un objeto.
- 🏀 En el punto inicial de un ejemplo con una pelota en una rampa, la energía cinética es 0 y la energía potencial es 500 julios.
- 🏔️ En el segundo punto, la energía potencial disminuye a 300 julios mientras que la energía cinética aumenta a 200 julios, manteniendo la energía mecánica constante en 500 julios.
- ⚡ En el tercer punto, la altura es 0, por lo que la energía potencial es 0 y la energía cinética es 500 julios.
- 🔄 El principio de conservación de la energía indica que la energía no se crea ni se destruye, solo se transforma entre energía potencial y cinética.
- 📏 Se puede usar la energía mecánica en puntos específicos para resolver problemas complejos, como calcular la altura máxima o la velocidad de un objeto.
- 🔢 En un ejemplo práctico, se calcula que la energía mecánica de una vara lanzada hacia arriba es constante en 0.32 julios.
- 🎯 La altura máxima que alcanza la vara se puede determinar usando la fórmula de energía potencial, resultando en 3.26 metros.
Q & A
¿Qué es la energía mecánica según el guion del video?
-La energía mecánica es la suma de la energía cinética y la energía potencial, y se mantiene constante a lo largo de un movimiento ideal sin la acción de fuerzas de fricción.
¿Cuál es la fórmula para calcular la energía potencial?
-La energía potencial se calcula mediante la fórmula: masa por gravedad por altura.
¿Cómo se determina la energía cinética en el momento en que un objeto se encuentra en reposo?
-Cuando un objeto está en reposo, su velocidad es 0 metros por segundo, por lo tanto, su energía cinética es 0 julios.
¿Cómo se calcula la energía cinética si se conoce la masa y la velocidad de un objeto?
-La energía cinética se calcula a través de la fórmula: 0.5 veces la masa por el cuadrado de la velocidad.
¿Qué principio se demuestra con la conservación de la energía mecánica en el video?
-El principio de conservación de la energía mecánica demuestra que la energía no se crea ni se destruye, sino que se transforma de una forma a otra, manteniendo una suma constante de energía mecánica a lo largo del tiempo.
¿Cómo se relaciona la energía potencial con la altura de un objeto?
-La energía potencial depende directamente de la altura a la que se encuentra un objeto, siendo mayor cuanto mayor sea la altura.
Si un objeto se lanza desde el suelo, ¿cuál será su energía mecánica inicial si la velocidad inicial es 0?
-Si la velocidad inicial es 0, la energía cinética inicial también será 0, por lo que toda la energía mecánica inicial será potencial y dependerá de la altura inicial y la masa del objeto.
¿Cómo se calcula la energía mecánica en el punto más alto de un lanzamiento si la velocidad es 0?
-En el punto más alto, donde la velocidad es 0, toda la energía mecánica se convierte en energía potencial, por lo que la energía mecánica en ese punto es igual a la energía potencial calculada con la fórmula: masa por gravedad por altura.
Si se sabe la energía mecánica y la energía potencial en un punto, ¿cómo se determina la energía cinética?
-Si se conoce la energía mecánica y la energía potencial en un punto, la energía cinética se determina restando la energía potencial de la energía mecánica.
¿Cómo se calcula la altura máxima a la que alcanzará un objeto lanzado si se conoce su energía mecánica inicial y su masa?
-La altura máxima se calcula utilizando la fórmula de la energía potencial y conociendo la energía mecánica inicial, dividiendo esta entre la masa del objeto, la gravedad y restando el resultado de la energía mecánica.
Outlines
🔬 Introducción al estudio de la energía mecánica
El vídeo comienza con Susi, quien nos presenta el tema de la energía mecánica, explicando que es la suma de la energía cinética y potencial. Se menciona que se trabajará bajo la hipótesis de ausencia de fuerzas de fricción. Se da una fórmula general para calcular la energía mecánica y se invita a los espectadores a explorar más sobre estos conceptos si lo desean. Se utiliza el ejemplo de una pelota en una rampa para ilustrar la conservación de la energía mecánica, mostrando cómo la energía cinética y potencial se transforman entre sí pero la suma total permanece constante.
🏋️♂️ Transformación de energía cinética y potencial
Susi profundiza en cómo la energía potencial se transforma en energía cinética a medida que la pelota se desplaza por la rampa. Se describe el proceso de conservación de energía mecánica, demostrando que a pesar de los cambios en la energía cinética y potencial, la suma de ambas permanece constante. Se utiliza el ejemplo de una cana lanzada para ejemplificar cómo calcular la energía mecánica, cinética y potencial en diferentes puntos del movimiento, resaltando la importancia de entender estos conceptos para resolver problemas relacionados.
📚 Cálculo de energías en diferentes puntos y altura máxima
El vídeo continúa con un problema práctico de lanzar una cana de 10 gramos a una velocidad de 8 metros por segundo. Se calcula la energía cinética y potencial en el punto de lanzamiento, en el punto a una altura de un metro y en el punto de máxima altura. Se demuestra cómo, conociendo la energía mecánica constante, se pueden encontrar las energías cinética y potencial en cada punto. Finalmente, se calcula la altura máxima que alcanzará la cana utilizando la fórmula de energía potencial y se resalta la importancia de comprender la transformación de energías para resolver problemas físicos.
Mindmap
Keywords
💡Energía mecánica
💡Energía potencial
💡Energía cinética
💡Principio de conservación de la energía
💡Gravedad
💡Joule
💡Velocidad
💡Masa
💡Altura
💡Energía constante
Highlights
Introducción al concepto de energía mecánica y su cálculo.
Explicación de los dos componentes clave: energía potencial y energía cinética.
La energía mecánica es la suma de la energía potencial y la energía cinética.
En ausencia de fuerzas de fricción, la energía mecánica se mantiene constante.
Fórmula de la energía mecánica: Energía potencial (masa × gravedad × altura) + Energía cinética (0.5 × masa × velocidad^2).
Descripción de un ejemplo práctico con una bola en una rampa y cómo varían las energías potencial y cinética.
La energía potencial depende de la altura, mientras que la energía cinética depende de la velocidad.
El principio de conservación de la energía: la energía ni se crea ni se destruye, solo se transforma.
Ejemplo de cómo la energía potencial se transforma en energía cinética cuando una bola cae.
En el punto más alto, la velocidad es cero, por lo que la energía cinética también es cero.
Cálculo detallado de la energía cinética y potencial en diferentes puntos de un problema de lanzamiento.
Explicación sobre cómo convertir la masa de gramos a kilogramos al resolver problemas.
Cálculo de la altura máxima que alcanzará un objeto usando la fórmula de la energía potencial.
Clarificación sobre el uso de unidades del sistema internacional para evitar errores.
Importancia de identificar puntos clave (inicial y final) en problemas para encontrar las energías correspondientes.
Transcripts
Hello everyone, I am Susi and welcome to my channel.
In this video we are going to learn what mechanical energy is and how to calculate it.
So let's get to it.
To be able to work with mechanical energy, to know what it is and to know how to calculate it, we must
know these two concepts before, potential energy and kinetic energy, because
mechanical energy is the sum of both. All this that we are going to see in this video is taking
into account this mechanical energy that is not going to act any force of friction, no force
that rests energy. If there is any force that acts as a force of friction, it would be
otherwise. Well, keeping that ideal situation in which there are no forces that act against
that energy, that is, that that energy rests, this would be the formula and we must then know that
potential energy is mass by gravity by height plus the kinetic energy, which is a medium, by
mass by the speed squared. If you need to go into more detail about each of these
concepts, potential energy and kinetic energy, click on the box that I explain more
in detail. Well, here as we see, the potential energy is that energy that is in a body
depending on the height at which that body is located. However, kinetic energy
depends on the speed at which that body goes at that moment, in which that kinetic energy is measured.
Suppose that here we have a ball that we throw on this ramp. Let's study this case for a moment
to understand now the principle of conservation of energy. At this initial moment, the speed,
the initial speed is 0 meters per second, right? So if we study kinetic energy here,
of this ball, kinetic energy is the one that depends on the volume, sorry, on the volume
of the speed, that would be a half of the mass that that ball had by the speed squared,
but since the speed is 0, kinetic energy therefore at this point is 0 joules.
Let's study potential energy at this point. Potential energy is the one that depends on the
height at which it is, therefore it will depend on the height that it has, the mass that it has. So, let's suppose,
let's assume that it is 500 joules of potential energy. What mechanical energy will it have in this
point 1, let's call it. In point 1, the mechanical energy of point 1 will be the sum of both, 0 plus 500
500 joules, right? I have invented, I have invented that imagine that we know the mass of the
body and we know what height it has at this point, it would be 500 joules. Well, let's suppose
that the ball here and here and we study it at this point 2, point 2. Here it does have
an acquired speed, right? Therefore, kinetic energy is no longer going to be 0. Let's suppose
that it gives us the speed that we calculate and suddenly we get that kinetic energy
has 200 joules and we calculate the potential energy. Here the height has already changed, the mass
has changed, therefore the potential energy varies and let's suppose that now it is 300 joules.
If now I assume the mechanical energy at this point, it would be 200 plus 300, 500.
And at this point 3, here it is important to know
that there is a speed, it has also increased, there is also what height the ball has at this
point, the height is 0, 0 meters. Therefore, what is going to happen to us with the potential energy? The
potential energy, which depends on the height, when it is 0, it multiplies everything and it will be 0.
Therefore, I already know that here the potential energy will be 0 and the kinetic energy,
yes or yes, will be 500 joules. And now we are going to understand all this that I have just described. Therefore,
if I add everything, 500 joules. As you can see, the mechanical energy will be the same throughout the
process, throughout the entire movement that this ball has. This is the principle of
conservation of energy. Energy is neither created nor destroyed, it is transformed and here you see it. At
this point the kinetic energy was 0 and the potential energy was 500. What has happened at this point?
The kinetic energy has been transformed, that is, the potential energy has decreased but in
return it has been reduced and there is kinetic energy. Part of the potential energy has been transformed
into kinetic energy. And here the same thing that has happened. The potential energy has been transformed
into kinetic energy. The point is that the mechanical energy has remained constant
throughout the entire movement that this ball has made. Therefore, this is something that we
must know. Mechanical energy is going to be a constant because I remember that energy
is neither created nor destroyed, it is transformed. You see, here it is very clear that it is transformed into another
type of energy. We go with kinetic and potential, you see that it is transforming but the
mechanics is a constant, it does not vary, it is 500 throughout this whole movement. Well,
this is very important to know at the point, we could call it at the initial point and at the final point
and in between what happens. The initial point and the final point can be used in many problems
to calculate the mechanical energy because knowing that at this point kinetic energy is 0,
I can find the potential energy and knowing the potential energy I am going to know then the
mechanical energy because here we see that the potential energy is going to be equal to the mechanical energy.
At this point 0. At this final point, what is going to be equal to mechanical energy? The kinetic energy.
So, knowing these different points where we can find ourselves, it will help us a lot
when it comes to solving the different problems that exist in this style. We are going to perform this problem
in which it tells us that from the ground we throw a cane up 10 grams of mass
at a speed of 8 meters per second. We throw the cane, it reaches this height and then it will go down.
What we have to calculate here is going to be at the initial point at one meter and at the final point
the kinetic energy, the potential energy and the mechanical energy in these three points.
We are going to do it to practice what we have just seen. So we are going to start. We must know then
in these three points, we are going to start if you want from the launch, that kinetic energy in
this case, we know that kinetic energy is the one that depends on the speed, we can calculate it, it would be
a half. For the mass, we have the mass of the cane, yes, 10 grams, but be careful, here you would make a mistake.
The mass here is always in kilograms, so it is not 10. We are going to pass it from kilogram to gram,
dividing by 1000, 0.01 kilograms. And the speed squared, what speed does it give me? 8 meters
divided by second, it is in the units of the international system, 8 squared. We calculate all this,
8 squared, 64 times 0.01 times 0.5, a half, 0.5, 0.32 joules.
With this I have found out the kinetic energy at this point.
The potential energy, what do we know about the potential energy at this point? We know that
by having height 0, because it is on the ground, 0 meters high, we will get 0, therefore,
the potential energy is 0 joules. Have you seen how easy it is in this case? And what would then be the
mechanical energy at this point? The sum of both, therefore, if I add 0 to 0.32, we have
that the mechanical energy, which is the sum of both, we get 0.32 joules. And surely someone has already
realized that since the mechanical energy that we have just seen, that throughout the whole process,
it will be the same, because it is a constant, we already know what the mechanical energy will be at this point
and what it will be at the highest point as well. It will be 0.32. So come on, it seems that we are doing
well. At this point we have to find out the potential energy and the kinetic energy as well,
and the mechanical energy that we already know. The potential energy at this point depends on the
height. We have height, yes, it gives us that it is one meter high. The gravity, 9.8, 9.81,
depends on the data you use. And the mass we also have it, therefore, come on, let's find out
the potential energy, because we have all the data. The mass, remember, the 10 grams are 0.01
kilograms. Gravity, I use 9.81. Height, one meter. Therefore, we multiply all this, 9.81,
by 0.01, 0.0981 joules. Potential energy, seen. The kinetic energy, for kinetic energy
I am going to need the speed at this point. I don't have it, but I just found out that the
mechanical energy is 0.32. So, if the mechanical energy is 0.32, if I also have the
potential energy, I have this and this, well, then I find out the kinetic energy in this way.
I have the mechanical energy equals the potential energy plus kinetic energy. Therefore, the
mechanical energy is 0.32. The potential energy, I just found out, 0.0981 plus the kinetic energy.
Therefore, the mirror is subtracting, the kinetic energy is going to be equal to the subtraction of 0.32
minus 0.0981. 0, I'm going to round, okay, to two decimals, 0.22 joules will be the kinetic energy
at this point. Here and here, you see? And the mechanical energy, I will not put it again, but at this point
it will be the same. We must know that, indeed, as it is a constant, it is the same
throughout the process. And now here, at the highest point, we are going to see. At the highest point,
what happened to us was that the speed, that is, once it rises, the highest point
reaches it when it reaches speed 0 and begins to fall. Therefore, at the highest point,
the speed will be 0 meters per second. With that, I know that this energy, that is, the kinetic energy,
is going to give me 0 joules, because there is no speed at that point. If I know that the kinetic energy
is 0 joules, I know that the total of the mechanical energy is going to be 0.32, in this case, therefore,
the potential energy is going to be equal to the mechanical energy, that is, 0.32 joules.
And with this we have already found out what this section of the problem asked us. In each point,
find out the kinetic energy, the potential energy and the mechanics. The mechanics, well, although I have not
written it all, it will be 0.32. But do you see these points? The initial point and the final point are
keys, they give us a lot of information. Thanks to having found out here that the kinetic energy,
in this case, 0.32, here coincides with the mechanical energy because the potential energy is 0
and from there we have been able to solve the rest of the energies in the different points.
And now we are going to find out one more part of this problem. In this section, what we have to do is
find out what is going to be that maximum height that the canister is going to reach, that is, what is going to be
that final height when it reaches speed 0 and then it starts to fall. Well, what is it going to be? How
would we find out? Think about it. At this point, the potential energy, which is taken into account
the height that you are asking me about, we know it. Do we know the potential energy? We know that
it is 0.32. I am going to put the formula here. We know that the potential energy is mass by gravity by
height. I have the potential energy because I have just found out 0.32. We also know that the mass
is 10 grams, which is 0.01 kilograms, by the gravity of 9.81 and what I have left out is the
height. Therefore, from here I found out the height. We are going to multiply 9.81 by 0.01 and we get
0.981 as we had put here and now, as this multiplication is on this side, I am going to
go here dividing to clear the height. I already have 0.32. I divide it by 0.0981 and I get
that the height is going to be 3.26, rounding to two decimals, meters. We are working with meters.
That is going to be the maximum height that this caneca is going to reach, that it has that mass, that it goes at that
initial speed, etc. You see how from there, already knowing clearly these two formulas and seeing
how kinetic and potential energy works along that movement of the body, I can
actually perform any problem and I can find out any of the incognitas demanded,
having these concepts clear.
And that's it for today's video. If you liked the video, give it a like and share it.
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