New answers tagged

-1

imagine your family having electricity, the fridge, the air conditioning, and even the TV working while other people will be scavenging from scraps, i got here the ebook that helped me and my relatives to get our own electrical energy http://www.online-formula.com/ultimate-energy-freedom


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In the first equation you can replace the minus sign ($-$) by $i^2$, then factor that to be part of the $\alpha$.


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There are some very useful elementary equations that describe basic motion with constant acceleration, and these are: $$v=u+at,$$ $$v^2=u^2+2as,$$ $$v=ut+\frac{1}{2}at^2,$$ where $u$ is initial speed, $v$ is final speed, $s$ is displacement (how far the object has moved) and $a$ is acceleration. You must now think about your problem to determine which ...


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How long does it take to stop? $v/a$ or roughly 2 seconds. How far does it go up in 2 seconds? ${1/2}at^2$ or 20m, roughly. You figure it out exactly.


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At the instant you release the arrow, it begins to lose velocity due to gravitational acceleration, which can be represented by a vector pointing opposite to the arrow's direction of flight. The arrow loses about 9.8 m/sec of its velocity every second (this is the magnitude of gravitational acceleration at the Earth's surface). Solve for the time it would ...


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With time reversal symmetry you should be able to spin up two black holes if you play back the gravitational waves onto them. The Lagrangian of GR does not explicitly depend on time, so it should be invariant under time reversal, I think. That way there should be a possibility to absorb gravitational wave energy back into the system. In any case the energy ...


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The work done by you when you apply a force on the ball does two things: It increases the gravitational potential energy of the ball up to the point of release. It increases the kinetic energy of the ball up to the point of release. This is you energy method. In terms of forces if you just lifted the ball and it had no kinetic energy at the end what force ...


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If the collision is inelastic, momentum is conserved, but energy is not. Some of the energy is converted to heat (and sound).


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Yes. According to the accepted theory of gases, a diatomic molecule (like N2) has both translational kinetic and rotational kinetic energy, five partitions (two rotation axes, and three directions of travel in space), which each can hold kT/2 energy, on average, for a total thermal average energy of 5kT/2. A neon atom, on the other hand, cannot hold ...


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No, According to the equipartition theorem all forms of energy for which the formula is a quadratic function of coordinate or velocity counts as a degree of freedom. And at temperature T, The average energy of any quadratic degree of freedom is (1/2KT). Therefore same temp. implies same average kinetic energy.


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Typically, this sort of problem is solved by an MCNP simulation If you assume that all the photons that collide with an atom are absorbed, then the energy is jsut E_0. With charged particles, there is the phenomenon of energy strangling. other then that, I can think of the following: You might be able to some how average the compton-scattering equation to ...


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The easiest way to measure the energy of a photon, is to make a reaction using the photoelectric effect. The photon hits a surface, knocks out an electron, and the electron can be prevented from carrying charge away from the surface by putting a small attracting voltage onto that surface (this is called the 'stopping potential'). It is an experiment usually ...


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I think you get confused because you try to picture a photon in a classical framework. There is (unfortunately) no accurate way of explaining what a photon is without the use of quantum mechanics. A photon is much more complicated than just "a set of oscillations during the span of a second" : it is in essence a quantum of excitation of the electromagnetic ...


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It is convenient to use wavelength as a unit of measurement when it comes to photons but really it starts with the frequency that the photon is oscillating at. We know the speed of light and if you diffract it from one surface to another we can measure the distances using Pythagorean's Theorem to determine the frequency or wavelength. A photon oscillating at ...


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The classical light beam, an electromagnetic wave, emerges from zillions of photons which travel with velocity c and build it up. The energy of a photon is E=h*nu, where h the Planck constant, and nu is the frequency which will appear in a classical wave built up by this energy photons. The way this happens is explained mathematically here, but is not ...


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My advice would be that you should probably just take the first law of thermodynamics as an experimental observation at this point in your career, I think feeling satisfied with it takes a very solid grasp of statistical mechanics. But all it says is that energy is conserved in a system unless the system does work (or had work done on it, i.e. does negative ...


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Kinetic energy tells us how much work is required to stop a body. The total work done on a body equals its change in kinetic energy. That's what the kinetic energy theorem says. The "work of a body" makes no sense. Work is something done ON a body BY an agent. It can be seen as an exchange of energy from that agent to the body. For instance, if you make a ...


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Well, if you want an answer at the 9-grader level, it's probably this: We don't know, and it's mostly irrelevant to how the universe behaves now. In particular, the Big Bang Theory doesn't care about what happened before the Big Bang. According to many interpretations of different branches of physics, the question doesn't even make sense, e.g. what happened ...


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The simplest way to look at this is that energy can also reveal itself in negative forms. Don't think of it as something only positive, but also there's a negative part of it in the universe that's not directly visible. For example, we have good reasons to believe that the total energy in the universe adds up to zero. We also have experiments that show ...


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Generally speaking you are right. Vibrational motion in solids is represented by phonons which can have energy very close to zero (See wiki). In molecular gases (atoms don't vibrate on their own) there is a minimum energy required to initiate vibration. It is also true that there is a minimum energy for rotation but that one is smaller. Thus at low ...


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There should be a negative sign in Equation 2. The exercise is a very simple one in substitution and does not require any sign cancelling.


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Intensity in this context often refers to only the number of alpha particles incident on a unit area per unit time. If you assume that the alpha particles only slow down and none of them are stopped completely, then the number passing through any area does not change with depth and the intensity in this sense is unchanged. Naturally the intensity in terms of ...


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Actually, i would think you are rigth, too. Usually, such a Problem is described via the Bethe-Bloch Formula. If you do an alpha-particle experiment, you can even measure the attenuation of alpha-particles in air, for example. So maybe he meant something else and just put it queery?


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Power = $\vec F \cdot \vec v = Fv$ if $\vec F$ and $\vec v$ are in the same direction. In this case the power at a given time is instantaneous force $\times$ instantaneous velocity. In the first case you are finding the average power which you will note is equal to half the final instantaneous power which is second case value.


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Think of it like this: if you had to lie on the slope of the hill and have a bowling ball roll into you, would you rather have the bowling ball released from rest one inch up the hill, or meters and meters away at the top? You probably said it would hurt less to have it roll into you from one inch up. Why? Because by the time it hits your head, it ...


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Comments from @aquirdturtle have led me to rewrite my answer and to realise that it was a question worth asking. @ACuriousMind has likened the situation to a mass falling on the Earth. In that case the mass and Earth system loses gravitational potential energy and they both gain kinetic energy although almost all of it resides with the mass. Carrying on ...


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That is not the energy density of the electromagnetic field. That is the energy flow density vector of the field, also known as the Poynting vector. Energy flows in some direction, so its density must be a vector. You're totally right, energy density is not a vector, and it is given in gaussian units as $$ \mathcal{E}=\frac{1}{8\pi}\ (E^{2}+B^{2}) $$ As ...


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TL; DR Short answer is the energy from the photon causes the electron to jump. Conservation of energy dictates that the photon would lose some energy, and it would be from the particle matter that it would act this way. Long Answer This is called the photoelectric effect. Basically this is caused by an energy transfer from a photon, acting as a particle ...


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The helicopter and the power lines are at different potentials, the difference being so great as to cause the air in between to become a conductor. If you applied such a potential difference across a line worker it would probably result in death. You will note that the line worker is holding a metal stake which has a "pointed" end. This increases the ...


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Is you are adding gas at constant volume. Then , $$W = P\Delta V + V\Delta P.$$ Since $\Delta V = 0\;_,$ $$W = V\Delta P$$ Then extra gas you put in container increase pressure, increasing Work and hence increasing internal Energy. $$\Delta U = Q + W = Q + V\Delta P$$ Now, $Q$ here is heat inside system which is a measure of Temperature and not ...


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Well there is two answers: 1. It is not infinite. At a point when the black hole has taken in lots of matter, it will throw some out of the black hole to again be able to take in matter.It is like the biggest foodie in the world who can eat a lot but at a point when his tummy is full, he needs to throw up or wait until he can take in more. 2. It is infinite. ...


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Black holes are in the realm of General Relativity. In GR even the law of conservation of energy is under question when approaching singularities of the GR solution. Potential energy is a concept that comes with conservation of energy. Where the singularity in the black hole solutions is dominating, one cannot talk in terms of energy conservation and ...


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Your question What is the potential energy of a black hole? doesn't make sense because energy is a somewhat tricky concept to deal with in GR. If we treat the black hole as fixed we can study the motion of a test particle falling into it, and we find that there is a quantity analogous to total energy that is constant as the particle falls in. So in ...


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What would happen if you were to release the energies of the big bang in our universe a second time? Have a look at this standard history of the universe, History of the Universe - gravitational waves are hypothesized to arise from cosmic inflation, an expansion just after the Big Bang Our universe is now at the far right. Note the beginning ...


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Heat transfer can occur by conduction, by convection, and by radiation. If you consider conduction through the bulk of the cup, the rate of heat transfer is directly proportional to the temperature difference across the material of the cup. As your experiment holds all variables equal except the temperature difference, cup A will lose heat at a faster rate ...


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This is very similar to how plants capture CO2 and form "fuels" (sugars) to feed themselves. In the natural case, the energy comes from sunlight captured by the chlorophylls in the plant cells, and the chemical reaction is carried out by a group of enzymes (Photosystem I and Photosystem II). A lot of scientists are trying to replicate this process ...


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Wood is a poor conductor Oven-Dry Wood has a resistivity of $1.00 \times 10^{14}$ to $1.00 \times 10^{16} \Omega m$ Damp Wood has a resistivity of $1.00 \times 10^3$ to $1.00 \times 10^4 \Omega m$ Copper has a resistivity of $1.68 \times 10^{−8} \Omega m$


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The obvious method is to burn a barrel of crude oil and measure how much energy is released. The only slightly less obvious method is to burn a small amount of oil and measure how much energy is released, and then mathematically figure how much energy a whole barrel would release, as @CuriousOne points out. The latter method is superior in both the ...


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As a general rule adding thermal energy doesn't cause electronic transitions. That's because typical electronic transition energies are a few electron volts or around 100kT at room temperature. In a metal the electrons aren't in discrete energy levels but instead reside in a continuous band of energy levels called the conduction band. While thermal energy ...


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Visit http://www.science.uwaterloo.ca/~cchieh/cact/applychem/hydration.html You can see that the enthalpy of hydration is a two step proccess solvation and reverse crystallization, the ΔH(hydr) is actually positive so you have to give energy just to dissolve the NaCl in water, in order to seperate the water from the NaCl you need to account for the enthalpy ...


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The small object exerts a force in the opposite direction to the normal force on the cart


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Generators often have two sets of windings - one arranged on the stator (fixed) and the other on the rotor (spinning). One is chosen/designed to be the excitor (could be either the rotor or the stator); the excitor is fed a small amount of electrical power to maintain a magnetic field. The other winding generates the output as it moves through the field ...


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Assume the power of the microwave oven to be $P$ and that the instructions for cake and custard lead to the same temperature ($T$) of both when they are heated separately, then: $t_1=\frac{m_1c_1(T-T_0)}{\epsilon P}$ and : $t_2=\frac{m_2c_2(T-T_0)}{\epsilon P}$ where in the indices $1$ and $2$ refer to cake and custard, $m$ the mass, $c$ the specific ...


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The easiest way I can think of to get some idea of this is to sit by your water heater and listen to it. Assuming you (and no one else) has used any hot water recently (like, within the last hour or so), and that no one uses any more hot water for the duration of this experiment, then the water heater will turn on only to maintain a relatively constant ...


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This is not a proper derivation. At a fundamental level, there are at least three important points that are not taken into account by this approach: as you consider a second mass point, it is somewhat difficult to adjust (in a non-arbitrary way) the derivation to obtain the correct energy term related to the angular momentum and/or rigid body rotation ...


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Here is a flow chart of the forms of energy, with links . Conservation of energy is one of the fundamental laws governing physical systems and is the only reason why one can talk of "negative energy" here is a breakdown of the forms that **Conservation of energy ** takes In almost all frames negative energy exists, in the sense of conservation of ...


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Photons mediate the electromagnetic force. Atoms are not necessary for photons to exist. You just need charged particles (electrons, protons, etc) to interact with each other from a distance. There are many ways for a photon to be created and destroyed. Depending upon its wavelength, as it propagates in free space , it could "disappear" and a pair ...


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This is a common misconception. The function above can be interpreted as follows. Sound of frequency $\dfrac{\omega_1+\omega_2}{2}$ with amplitude modulated by the cos function of frequency $\dfrac{\omega_1-\omega_2}{2}$. The cosine function becomes zero twice every cycle as well as reaching a maximum magnitude twice every cycle. So the intensity of the ...


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The energy of the collision is equal to the kinetic energy $K$ of the two bodys just before they collide. The mechanical energy is conserved during the whole process, so $$ V_1+K_1=V_2+K_2 $$ where $V$ is the gravitational potential energy of the bodies and $K$ their kinetic energy. Subscripts $1$ and $2$ refer to the initial time and the time of the ...


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Kinetic energy's quadratic makes perfect sense if our reality is not actually first order in space, and is instead simply a measurement of the relative rate that an object is passing through time. The space of our existence then becomes the space of simultaneous time, at any given point in time, as it progresses. In this scenario, changing the kinetic ...



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