Energy conversion Definition and 84 Threads

I asked this question about one year ago, but at that time I didn't really understand what I was doing. After spending a lot of time in this problem, I still fail to get the asked answer. Starting with ##\frac{De}{Dt} + (\gamma - 1)e \nabla \cdot \vec{u} = - \frac{1}{\rho} (\vec{u} \cdot...

This may seem like an obvious and foolish question intuitively, but I am curious about something. Let's assume we are performing a biceps curl exercise. To properly analyze human movement, a much more complex process is needed, but I will simplify it as much as possible. As the name of the...

Hey there, First of all, all energy conservation equations for a fluid I found on google hadn't the ##\gamma## coefficient. What exactly is the difference? Secondly, by substituting e by ##e = \frac{1}{\gamma -1} \frac{p}{\rho}## in the following equation ##\frac{De}{Dt} + (\gamma - 1)e \nabla...

So, I cannot for the life of me write a conservation of energy statement, when an object is lifted up by a force. So in my example there is a box on the floor with v = 0, and then a force of magnitude F, where F > mg, acts on the ball, now the net force is F-mg, and hence the work done is (F -...

Usually, I like to take a physical approach to phenomena that occur in everyday life. But I feel difficult to solve problems because I don't have higher education My question stems from this question (What's the difference between running up a hill and running up an inclined treadmill?), which...

Here, I have assumed very quick movement of the moving part. So, as per the mmf-flux curve, flux linking with the system will be unchanged during the movement. To support this assumption, I have made use of the following analysis. In this graph, the movement of the part happens quickly (small...

I'm trying to come up with a design for a handheld pump that will be used to suck diesel from a car's fuel tank. There's definitely going to be a pipe dipping into the fuel tank, and there's definitely going to be a human manually operating the pump. I'm trying to think of a mechanism that...

Hello Gents, I am very confused about the working principle of gas turbines. I understand that air is first compressed in a compressor to obtain high pressure air at the inlet of turbine, but before air is introduced to the turbine, first it has to be heated to very high temperatures through...

Good day everyone, I've recently been researching direct energy conversion schemes for nuclear fission, and I have a question on the basic physics behind the device (specifically on how it converts kinetic energy to electricity). In essence, the "basic" scheme for fission DEC devices is that...

Why I cannot get the right answer by using △T=(3/2)nK△T to solve problem C：

Hello, I am interested in the circuitry of energy conversion, such as solar, thermal, etc. How does the converted electrical energy get stored, for example, do they use supercapacitors? How does it then get applied for general use? Do you have any documentation or circuit diagrams for this?

A while back I made a thread which helped me even though it went sideways at the end, now I have one (maybe few) questions.1) So in a klystron, the current running in the output cavity torus as the bunched electron beam passes through the output cavity center is directly proportional to the...

Hi all, this is my first post. It seems around eight years ago I was on a similar brain-wave-length as Laurence Kemball-Cook, with his idea to create a power generating flooring surface... only he had the know-how to bring the idea to market, so credit where credit is due. (though now I wonder...

Okay...Suppose we we lift up something from the ground upto a certain height. By doing so, we have imparted it some potential energy. If we now let go, it will start converting its potential energy to kinetic energy.Now, suppose we apply this analogy to the case of a positive charge place nearer...

I have selected a topic for my research work which is "nanostructured materials for solar energy conversion" I have read many of articles, most of which are about Li batteries but I want to do something new. Anyone who's in this field suggests something new.:smile:

Hello, I read that in a scintillator before the photomultiplier tube is a crystal or sometimes gas or even sometimes a plastic, in other words a material which exerts luminosity under ionizing radiation. Say in the doped crystal for example, a high energy photon of say several Mev hits the...

I was thinking about the law of conservation of energy, states that energy can neither be created nor destroyed. Then I thought about it more broadly, it actually states that the universe was created with a fixed amount of energy (and this energy only transforms from one form to another) And...

Homework Statement Homework EquationsThe Attempt at a Solution I'm quite new to these chapters and I can't seem to get my head around the theory and especially this question. That's the solution above. Where does the T_max = 1/8... equation come from? I understand that the mechanical work...

Homework Statement I was looking for some examples where gravitational potential energy is converted to heat energy. Are there many such examples of this conversion? I could only come up with one such example and even that could be an incorrect example. Homework Equations PEg = mgh The...

Hi all, I would like to know what's the kind of work a mechanical engineer has to perform when being part of the team encharged of building a fusion or a generic nuclear reactor. I find many areas in mechanical engineering attractive, but I believe that fusion reactors have great potential in...

You can burn a hole in paper using a magnifying glass and light. What would happen if you applied this large-scale on a solar panel?

This is a fun thought experiment; Why not have space based mirrors to reflect light down to Earth at night to make solar do a little extra generating! The cost of solar is coming down and the cost of lifting things into orbit is coming down, so why not. Plus gold is very reflective, light...

Technically, this isn't a question concerning supercritical fluids. It's more about converting thermal energy into velocity by playing "keep-away" with molecules that want to go supercritical. The idea is simple. In an fully contained system, we can more or less say volume is static...

Homework Statement Looking for some feedback a) Describe the energy conversions in a spring undergoing simple harmonic motion as it moves from the point of maximum compression to maximum stretch in a frictionless envoirnment. Be sure to point out the points at which there will be I) maximum...

Hi guys I am working on a project in which i use solar panels to drive a pair of headphones my main question is what kind of solar panels would you guys recommend? that could help with this kind of project

I'm seeking comments & opinions on a couple of statements I've come across in a book: "A textbook of electrical technology" https://books.google.co.uk/books?id=1lR701DFtaMC&pg=PA997&source=bl&ots=9XfjSFr7cR&sig=KK_WAbdNVCdCWUWiHUxUrtcpjug&hl=en&sa=X&ved=0ahUKEwiI9MH7ntTKAhXDRhQKHalHBEAQ6AEIHzAD...

I regret to say that I know little of engineering, but, to make a long story short, I'm nagged by two questions about energy conversion efficiency. There is a thread i made titled "giant railguns recycling their own energy in space" in the science fiction & fantasy forum here that explains my...

Hi people. I'm currently well into my 4th novel, 'The Atlas of Elegance.' it's a book about magic - but a kind of magic based around physics, in particular quantum and astrophysics. The main characters in the story have the ability to control matter at a sub-atomic and quantum level. I'm using...

Homework Statement So I have a horizontal pulley positioned at the edge of table with a mass of .2kg hanging down from a height of .76meters, the other end of the string is attached to a wooden block of mass .25kg that when the .2kg weight is dropped the wooden block is pulled towards the...

I have a question about direct energy conversion; if I want to directly extract electrical energy from the fusion reaction p+Li-7 reaction which generates He nuclei, with a kinetic energy of 8 MeV, what is the most suitable method of doing that? Should some method with charge separation be used...

We say the expansion coefficient of steel is 12 × 10 -6 m/m°C, Young's modulus 210 × 109 N/m2 and yield stress 250 mega Pascal. With 100 meters length and 0.1 m2 section area , If we increase its temperature 10 °C, how much energy will be produced by expansion force in Joules? with young's...

As we know that every object that has kinetic energy could also have potential energy. Now suppose an object is in rest at a distance of h meter from ground so it has some potential energy and no kinetic energy, now if it starts to fall towards the ground can we say that its total potential...

Hello everyone, Imagine two points that have a Electric Potential Difference of 10V and they are connected through a conductor wire. Let's call these points A and B: Now imagine we have a charge on A of 1C. To move the charge to B, we need to make a work of 10J, right? So, now, imagine the...

Hi, I was wondering if someone can explain to me the following. If I have a vibrating molecule in a solution, what effect would this vibration have on other particles in my solution which are different. Can the vibration be the same for them if they are not excited (do not vibrate due to...

Can anyone tell me how energy created via the Penrose process can be extracted and converted into useable energy? What kind of infrastructure would we need on Earth, in space, etc.? Many articles talk about how energy can be created through the Penrose / Blandford–Znajek process, but none...

Homework Statement A 1100kg car is traveling at 24m/s before it hits a 18m patch of mud with a 1.7 x 10^4 net horizontal resistive force. What is the cars speed as it leaves the mud patch? Homework Equations Change in Uint= fd KE= 1/2mv^2 W= Fd The Attempt at a Solution 1/2mv^2 = f(mud on...

A recent issue of Aviation Week described a novel design for a fusion reactor from the Lockheed Skunk Works. It was smaller, simpler and lighter than the extant systems now being built and they're optimistic about it's test run in five years. I wrote a letter to the editor touting this departure...

Homework Statement [/B] Suppose the main water pipe breaks in a nuclear power plant, shutting off the water flow. If the control rods fall immediately into place, stopping the chain reaction, is there still a problem? Yes, because radioactivity continues to create lots of thermal energy. (A)...

A man is running and chemical energy converts to thermal and kinetic. The output (thermal and kinetic ) has the same amount of energy as the input (chemical). But what does thermal and kinetic energy convert to?

Hi, all I'm seeking advice on how to calculate the energy conversion efficiency, in case of heat from light energy. I think that one of the general formulas 'energy output/energy input' can not be applied in this problem. Assuming that light(or laser) has 10W power output and material 1...

Hello, Assume a synchronous generator is running unloaded and has a fixed input power for any given short time frame (which is a practical consideration for electric power plants). When an electrical load is applied, the machine slows down. I understand this.. what I don't understand is the...

(this is the first time I post. hope this is in the correct board) So I want to know about how the internal energy of water has been converted into electrical energy when the turbine is rotating at a steady speed. I have read several textbooks and they all give me several answers: 1. GPE of...

Homework Statement A very short 100 kg acrobat steps off a 10 m high platform and starts falling. The acrobat falls 9 m, then encounters a 1 m long spring connected at one end to the ground below. (a) What’s the spring constant so the acrobat just touches the ground (that is, so the...

1. i drop a ball (mass 20 grammes) from a height of 10 meters, after 3 bounces it rises to a height of 2 meters, what is the energy conversion efficiency of each bounce? 2. I've been stuck on this for the last hour and have nothing any help would be great. 3.the closest i got was...

This is just a very simple conceptual question. Say that someone is going down an escalator at a constant velocity. They are losing GPE, but not gaining any KE. So where is this potential energy going? Same with going up, they're gaining GPE, but not losing any KE. On a similar note, say...

New here, hello all. My question is more about the field magnet in a running DC motor. First of all, does the current required to maintain a magnetic field change with the load on the motor? And if so, where would this "extra energy" come from in a permanent magnet DC motor?

Homework Statement The positive terminals of two batteries with emf's of V_1 and V_2, respectively, are connected together. It is V_2>V_1. The circuit is completed by connecting the negative terminals. If each battery has an internal resistance r, what is the rate with which electrical...

Hi there people, I have a doubt, if you convert all energy has an expense which makes it is always converted less than 100 percent for example kinetic energy turning electrical energy turning 90 percent of electrical energy, there was a loss of the energy that I'd like to know and if for example...

I've come across one thing about energy conversions: "To make an energy conversion possible, it is important that the supplied form of energy must be opposed by another force, otherwise this energy cannot be converted." Agreed! Once the motor starts generating torque, a back emf is produced...

Energy Conversion Explanation I have a ball behind suspended at the top of a ramp. The ball rolls down the ramp and triggers a switch. The switch is connected to a 9V battery and a motor and turns on once the switch is pressed. The motor acts as a fan because it has "blades" attached to it...