Questions tagged [energy]
The energy tag has no usage guidance.
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How do cars move, it seems inexplicable (to me)?
Confiteor, I have only a rudimentary knowledge of how machines work. I'll be discussing fossil fuel engines only.
First off, I have a block of iron, B. I find a pan balance. I place B in one of the ...
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Kindly explain this graph which is related to internal combustion engines
Hello,
I am not getting this graph which is related to the Internal Combustion Engine.
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1
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72
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Blasting - how to calculate the charge concentration Ib (kg/m)?
I posted this question in physics, but they advise me to post it here so here I am.
I was looking for the formula to calculate the burden in bench blasting and I found this document. The problem is I ...
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Options for generating electricity for autonomous platform while at sea?
I am building an autonomous platform (2m x 2m) that I intend to deploy to the sea. To power various sensors and actuators I will make use of solar panels, but it occurred to me that there might be ...
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Elevator idle power where does it go to
We have a hydraulic elevator in our 4-storey building which appears to be using quite a lot of energy even at night when it is not in use. I measured an average of 3 kWh of energy over a 10-hour time ...
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natural gas-fired power plants
I live in Tunisia, a country of 12 million inhabitants where natural gas (provided essentially by Algeria) is used in power plants. I'd like to know how it is that natural gas can contain so much ...
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Calculation of work to create a vaccum
I am trying to calculate the work required to lower the pressure in a box from P1 = 1 bar to P2 = 0.1 bar. The box has volume V. Is this simply VdP work? If not, how do I perform an energy analysis to ...
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Do wind turbines placed on the sides of roads, powered by vehicles traversing the roads (traffic turbines) actually work?
Recently, ActionLab has posted this video https://www.youtube.com/watch?v=W8Oc3Etev34&t=1s, titled "Do Traffic Turbines Actually Work". It has caused a heated debate, as people discussed ...
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Does triboelectric generator made with powder and wire mesh work?
One of the greatest challenges for triboelectric generators is surface charge, which ultimately depends on surface area. Why don't we make one triboelectric layer a powdered form and a crazy forest of ...
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When fluid hits a surface or object, why doesn't its energy decrease?
In turbojet (gas turbine engines), we analyze fluid in terms of pressure. We say that when fluid/air hits stator of compressor, its velocity decreases but static pressure increases due to Bernoulli ...
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Wind triboelectricity shakers in series
I've seen shaker generators made with small plastic hemispheres with aluminum foil stuck on inside both, and a small ball wrapped in tape put in and sealed up. Then the shaker is vibrated and it ...
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119
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Effect of Earth's rotation on moving vehicles
The earth rotates at a rate of 460 m/second. I wish to predict the position and approach for landing an UAV (quadcopter) on the vehicle.
I have a free-moving landing platform on vehicle that aligns ...
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stress power of a solid
In the balance of mechanical energy https://pkel015.connect.amazon.auckland.ac.nz/SolidMechanicsBooks/Part_III/Chapter_3_Stress_Mass_Momentum/Stress_Balance_Principles_08_Cons_of_Mech_Energy.pdf,
$\...
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What mathematical operation should I do in order to translate from TWyr/y to TWyr_30 in this article?
In this article
https://www.sciencedirect.com/science/article/pii/S266711312200002X
the authors show a result of prediction on energy reserves (in particular solar ones) as known in 2015 (Figure 1) ...
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Does a typical domestic combination boiler have different burn rates?
For a typical domestic combination boiler, does it have different burn rates, in a similar way that a gas hob ring has? My understanding is that the trigger for whether such a boiler comes on or not ...
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How to match a synchronous generator with a powered shaft?
Given is a shaft powered by a steam turbine that rotates unloaded (i.e without generator) at $ \omega $ rad/s and a torque of $T$ Nm. How would one match a generator to extract power requiring a ...
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How are a Horizontal Axis Wind Turbine's blades joined to the hub, allowing them to rotate?
I know its a basic question for this site.
But I couldn't find the answer on google so I beseech thee.
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how to fix an object at either 90degree or 0 degree
my problem is i donot know how to let the blue colored object be fixed at either 0 or 90 degree.
i dnot want to be moveable at any degree like 30, 40 , or 50 degree either 0 or 90 degree.
i have tried ...
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Force Required to Keep Ball Rolling
I am attempting to recreate a demonstration that someone told me about. A hollow steel ball rolls around in a non-metalic bowl, electromagnets keep it going. I obtained a steel ball and a glass ...
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Are there any ad-hoc uses for electricity that we can divert excess energy to when renewables are peaking?
My idea is this: divert excess energy that comes from peak renewable energy production to ad-hoc public works whenever we have more than we can put in batteries. I just don't know what things like ...
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mg996r - maximum weight for robot arm [closed]
I want to build a robot arm (see https://youtu.be/F0ZvF-FbCr0) to move a dumbbell of 2 kg (roughly 2.2 lbs).
However, since I have no background in engineering, I have no idea how to calculate / find ...
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Suggestions for mechanisms for slowly releasing gravitational energy
I'm searching for a mechanism to slowly release gravitational energy. I've attached an image of an example scenario where a 10kg weight slowly raises the 1kg weight over a set period of time, for ...
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Principle of virtual work "geometric proof"
I spent a full day searching for and trying to understand why in this "proof" of virtual work makes sense. I've come to understand the idea from D'Alambert's principle, but I want to ...
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Are internal combustion engine more efficient than steam turbines
From what i understand the indicated thermal efficiency of an ic engine is measured at the fly wheel and is the measure of the amount of thermal energy being converted to mechanical energy please ...
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Calculate uphill efficiency on different gears
I was interested to find whether it would be more efficient to climb a hill on a lower gear, so I did some calculations.
I have the following data of a custom vehicle:
Gear
Drive force (N)
Max speed (...
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What should be the clearance and creepage for the line to line 440 Vac and line to neutral 240 Vac of the three-phase system on PCB?
Also is there any link to calculate this as per the UL and other industrial standards
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Boiling water efficiency [closed]
What is the most efficient method to boil water without thermal energy. eg. burning gas. Reducing pressure reduces the energy required but is there something on a molecular level that is the most ...
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Strain energy, Conservative force and Potential energy
What I know:
In general, the work done by a conservative force $F$ is equal to the negative change in a potential energy.
$$\int_1 ^2F.ds = - (U_2 - U_1) $$
A potential energy is always associated ...
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What are some methods of converting electricity without the use of induction or heat?
I was trying to study exactly how current in a wire is used to do so much in our life and how the energy is converted. But the only methods I have found are by using the resistance of the conductor to ...
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146
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Can two microphones placed within centimeter distance together measure a distance of the sound source?
I have placed two microphones placed within 1 or 2 cm distance. They can receive and record sounds around them. I want to detect the distance of the sound source (specially human voice) and the ...
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Changing temperature under adibiatic conditions?
Can a temperature change be adiabatic? For example if no 'heat' leaves or enters the system and we compress a fluid such that it's temperature changes is this still adiabatic? If energy is transferred ...
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Sign Convention for Energy Methods in Vibration Analysis
Find the equivalent spring stiffness of the system below.
I was able to solve it using Newton's second law and got the result below.
$$ k_{eq} = \frac{mgl}{2} - \frac{k_1 l^2}{16} - k_2 l^2$$
However,...
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how much energy is stored in a car under sun ? (car interior)
When a car is under the sun, the interior is hot. This is due to the interior, especially seats, which are black (or a dark color) so that they heat under sun light and restitute this heat to the air. ...
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Different equations for Hydropower
I was doing some reading in hydropower and I came across these two power equations:
$$P = ρghQ $$
and
$$ P = QHg $$
Q is flow rate, ρ is water density, g is gravity, h is height, and H is head.
I do ...
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Net force exerted by spring
I want to find the exact net force exerted by the spring between pt. P and C, when it is compressed till point P with some mass, m attached to it and released (assuming spring goes to pt. C after its ...
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Area under Frequency response function (amplitude vs frequency)
Recently, I was plotting frequency responses of multi-degree spring-mass systems and I was wondering what does the area under the FRF (amplitude vs frequency) (or in general FFT) mean? Does it have ...
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Total Kinetic Energy of a System with a Body Inside Another for Lagrange's Equation
Suppose a bus with mass $m_1$ moving horizontally with velocity $\dot{x}_1$, and a person with mass $m_2$ running with velocity $\dot{x}_2$ inside the vehicle. What is the total kinetic energy of the ...
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Heating pump/refrigerator - calculate efficiency
I'm wondering how I can calculate the overall thermal efficiency of my heating/refrigerator pump.
Actually I have this AC/heating pump unit from Samsung (P/N: AR09TXFYBWKNEE).
I've placed a power ...
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Is the main goal for wind turbines to take maximum energy for a given diameter?
If you increase the number of blades, that will increase torque, for the same RPM you get more power,...simple logic
So why only three blades, is main goal for wind turbine take maximum energy for ...
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Energy consumed by a two-link planar manipulator with feedback control
I was carrying out a problem in which I have a fully actuated two link manipulator, so with an independent servo motor for each link that allows rotation in one direction and another (positive for ...
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What happens to generated electricity if it is not used?
Let's take for example hydroelectricity produced at a dam and not consumed by any household or industry... Will the electricity need to be stored? What will happen if it is not stored? Does it flow ...
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What is the maximum distance for eavesdropping? [closed]
There is a closed question
https://physics.stackexchange.com/questions/276667/what-is-the-maximum-distance-for-eavesdropping-sound-waves
on Physics Stack Exchange and I thought this might fit better ...
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Why does "potential energy" have the word "potential" in it?
Imagine a block of mass $m$ placed on the ground. I slowly lift it up to height $h$. The work done by me on the block is $mgh$. This amount of energy is now stored in the block when it is at height $h$...
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How do you estimate the energy of an impact?
I am trying to determine the energy of elastic stress waves generated in a solid by an impact. I have a time domain waveform from a piezoelectric transducer that was placed next to the impact site, as ...
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How to convert car power into energy (MJ) used per km?
I am currently attempting to do an energy audit regarding how much energy my car uses per kilometer. I am not sure whether my approach to this is right, and it feels like I have made too many ...
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Understanding "total primary energy supply"
I am trying to wrap my head around the diagram and explanation here but can not understand completely how it is computed.
https://energyeducation.ca/encyclopedia/Total_primary_energy_supply
For ...
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Converting between MMBTU and MWh
a quick question:
I want to convert between MMBTU and MWh to get at emission factors from energy.
I have the following information:
I use the data given in 40 CFR 98 (see EPA source here) by the EPA ...
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Dehumidification calculations
I'm looking at options for DIY dehumidification and am hoping to get a sanity check on some calculations, and verification that I'm using the right factors in the right way.
As a reference point, I ...
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If the developing countries consumed as much energy per capita as China how much the current energy need would grow?
I recently saw this question and I immediately thought that the discussion was too limited to current energy production, it simply assumes that the amount of energy we use today is the amount of ...
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How do 3 blade turbines come so close to the Betz Limit?
I have seen many diagrams (see attached) that indicate that modern 3 blade turbines are nearly 50% efficient, which is about 80% of the Betz limit.
Betz calculated his limit based on a theoretical ...
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