Ground Definition and 945 Threads

Its attached below. I don't understand how you work out the total head. Can someone explain how you do it? I'm really struggling. I know how to do the elevation, which is just the height above/below the datum level. And I've checked the solutions as well, it seems like you're supposed to work...

Homework Statement The Hamiltonian of helium can be expressed as the sum of two hydrogen Hamiltonians and that of the Coulomb interaction of two electrons. \hat H = \hat H_1 + \hat H_2 + \hat H_{1,2} The wave function for parahelium (spin = 0) is \psi(1,2) = \psi_S(r_1, r_2)\dot...

Homework Statement A 14kg mass is attached to one side of a vertical pulley and an 8kg to the other. The 14kg mass is 5m above the ground. The 8kg is just resting on the ground. The pulley is frictionless and weightless. Find the velocity of the 14kg mass just before it hits the...

Why does a voltage tester (that looks like a screwdriver) turn on even when you are "heavily" insulated from the ground e.g. sitting on a wooden chair. Is it the result of capacitance between the human body and the ground? (i.e. the body and the ground act as conductors, whereas the insulated...

Homework Statement A case is being pulled along horizontal ground by means of a rope. Show that the force required to keep the case moving at constant velocity along the ground is a minimum when the rope is at an angle θ to the horizontal, where: tanθ=\muk Homework Equations...

Homework Statement 2N fermions of mass m are confined by the potential U(x)=1/2(k)(x2) (harmonic oscillator) What is the ground state energy of the system? Homework Equations V(x)=1/2m(ω2)(x2) The Attempt at a Solution I know the ground state energy of a simple harmonic...

I was thinking of putting together a visualization of electron orbitals as it transitions from unbounded or weakly bounded state to the ground state. However, it occurred to me that orbitals are symmetric about the proton. At some point the probability distribution must become asymmetric...

¿Why the forces in the arch are carried to the ground? Homework Statement Hello, I want to know if my argue is right. The question is to justificate why the forces in the arch are carried to the ground. I suppose a three voussoir's rounded arch. Just the arch, no structure supported. I call...

Homework Statement The interaction between the spins of the two particles in a hydrogenic atom can be described by the interaction Hamiltonian $$\hat{H_I} = A \hat{S_1} \cdot \hat{S_2}.$$ Compute the splitting of the ground state due to ##\hat{H_I}##. Both particles have spin 1/2. Homework...

My textbook says the ground state energy of the QSHO is given by 1/2*h_bar*w and that this is the minimum energy consistent with the uncertainty principle. However I am having trouble deriving this myself... ΔEΔt ≥ h_bar / 2.. so then ΔE/Δfrequency ≥ h_bar / 2... ΔE*2*pi / w ≥ h_bar / 2 ΔE ≥...

Shielding -- Need to ground an electrostatic shield? I am reading this app note by analog devices: http://www.analog.com/static/imported-files/application_notes/41727248AN_347.pdf At the bottom of the first page it says: "An electrostatic shield, to be effective..." "But grounding the...

I am reading an article on wikipedia about ground state and it says - The ground state of a quantum mechanical system is its lowest-energy state; the energy of the ground state is known as the zero-point energy of the system. An excited state is any state with energy greater than the...

Homework Statement The normalized energy eigenfunction of the ground state of the hydrogen atom is ##u_{100}(\underline{r}) = C \exp (-r/a_o)##, ##a_o## the Bohr radius. For this state calculate 1)##C## 2)The radial distribution function, the probability that the electron is within a...

Just curious: if an electron absorbs a photon of energy, it is in an excited state. The electron may go to a lower energy state (but NOT the ground state). Can a photon (of higher wavelength than absorbed) be emitted still? I don't quite see the importance of the electron having to go to the...

In my book it is mentioned that for the two 1s electrons the ground state is the singlet while for the two 2p electrons the ground state could be either singlet or triplet. Generally how can you determine whether the ground state is singlet or triplet?

First of all, excuse me if this question is too basic: I feel like it shouldn't be a struggle to understand, but the fact is it is. We put up an antenna to play with radio a little, and someone we were working with showed us that there's a reading on the voltmeter without any of the equipment...

Homework Statement While playing around with basic QM, I tried using the hamilton operator to find the kinetic energy of a hydrogen atom in its ground state. I assume the wave function ##\psi_1## is known. However, I of course ran into problems... 1) in my solution attempt below, I end up with...

For a University project I need to somehow model the effective performance of a ground grid in the event of a fault caused by a lightning strike. We would need to prepare different test cases for different sizes and grid configurations in order to carry out different analysis and find the...

Homework Statement An electron in hydrogen atom can be described with normalized wavefunction ##\psi (r,\vartheta ,\varphi )=(\frac{1}{64\pi r_B^3})^{\frac{1}{2}}exp(-\frac{r}{4r_B})##. Calculate the probability that the electron is in ground state of hydrogen atom. How much is the energy...

I've recently realized I have completely taken for granted that electrons simply tend to be found in their ground state. I want to understand fundamentally what is causing the electron to drop back to its ground state. It feels a force from the positively charged nucleus, but if it was given...

Homework Statement Prove that a projectile launched on level ground reaches maximum height midway along its trajectory. The Attempt at a Solution Is the attached solution the correct way to prove? I tried another method which was: t = 0 or t = 2vyi/g [y(2vyi/g) = y(0) + vi.t -0.5gt^2]/2...

Shouldn't the integrating factor be ##exp(\frac{m\omega x}{\hbar})##? \frac{\partial <x|0>}{\partial x} + \frac{m\omega x}{\hbar} <x|0> = 0 This is in the form: \frac{\partial y}{\partial x} + P_{(x)} y = Q_{(x)} Where I.F. is ##exp (\int (P_{(x)} dx)##

Here is the question: I have posted a link there to this thread so the OP can view my work.

Homework Statement A)A ladder of weight 80N rests against a smooth wall at an angle of 29 degrees to the vertical with its end on a rough horizontal floor.If the ladder is in equillibrium calculate the reaction (magnitude and direction) of the ground and the wall. Bi)a man of weight 80N...

Homework Statement Suppose a wheel with radius R is resting on a non-inclined surface. A torque \tau is applied to the wheel center. In an attempt to prevent wheel from spinning, the ground applies a static friction force to the wheel at the contact point (parallel to the surface), then the...

I have confounded myself with the following observation. Take the standard expression for the lowest energy Dirac 4-spinor solution of the Dirac equation with a Coulomb potential (the H atom ground state). Plug this into the standard expression for the 4-vector current and use values for the...

If a Hamiltonian is unbounded from below, say the hydrogen atom where the Hamiltonian is -∞ at r=0, is there a way to tell if the ground state is bounded (e.g. hydrogen is -13.6 eV and not -∞ eV)? It seems if the potential is 1/r^2 or less, then the energy will be finite as: \int d^3 r (1/r^2)...

Homework Statement You toss a ball straight up at 7.3ms^-1; it leaves your hand at 1.5m above the floor. a) Find its velocity before it hits the floor b) Suppose ball is tossed straight down at 7.3ms^-1, what is the final velocity just before it hits the floor. c) When would the second ball...

I need someone to check my work, because I am getting very weird numbers. Just want to make sure I am doing this right... The height of an object in meters after t seconds is given by H(t) = 152t - 16t^2. a) When does it hit the ground? My answer: t(152 - 16t) = 0 which means t = 0, t =...

Homework Statement Calculate the magnetic moment of the ground state of \,_{20}^{39}Ca. Compare to the experimental value in table 1. Homework Equations Nuclear Shell Model knowledge The Attempt at a Solution Well firstly the magnetic moment of the nucleus similar to the spin is...

Homework Statement A girl is on a ride at an amusement park. She is 30m above the ground and is ascending vertically at 5.0 m/s. While she is ascending, she holds her arm out and releases a penny. How long does it take th penny to reach the ground? Homework Equations y=yi+vit+0.5(at^2)...

The term ground has always confused me. For instance: I have always thought of a battery as a collection of negative charges at the -pole and positive charges at the +pole. But with this picture what does it mean that one pole is grounded. To be grounded is I guess ideally to be connected to the...

Does the ground wire used in transmission/distribution systems also serve as a neutral wire in some cases or is it used only to protect the conductors against lightning strikes?

Homework Statement In my homework I have to determine how do the speed (constant speed) (V) of damped mass and geometric characterictis of ground (b, h) influence on oscillation values of a model represented on a picture below. Model represents a vehicle driving on a sine wave ground. I...

Hello everybody, I have a question which might be silly. Nevertheless: Can exited states exist if you know that the ground state do not exist? Will in such a case first exited state become the ground state? Thanks.

Homework Statement A particle is in the ground state of a simple harmonic oscillator, potential → V(x)=\frac{1}{2}mω^{2}x^{2} Imagine that you are in the ground state |0⟩ of the 1DSHO, and you operate on it with the momentum operator p, in terms of the a and a† operators. What is the...

If we drop a charged particle and a neutral particle at the same time(same hight) in a uniform gravitaional field, they will hit the ground simultaneously? on one hand：a freely falling charged particle will radiate according to a supported observer, so the radiation recoil (radiation...

This is a question that me and a friend have been wondering. He says that when the ball hits the ground and is at rest for a very brief moment, potential energy will be 0 in the center of the ball, while I thought that it doesn't matter as the entire ball's potential energy is at 0. Which answer...

I have checked How Stuff Work, About.com, Ask.com, Google and even asked an electrical engineer and found no satisfying answer to the following questions: For household AC current, why do we need 2 live, a neutral and a ground 4-wire connection? We get 3 wires from the street transformer where...

I am reading the book "Lecture notes on Electron Correlation and Magnetism" by Patrik Fazekas. It says, "The ground state (of Heisenberg FM model) is not unique. We have just found that the system has the maximum value of the total spin Stot = LS. Sztot = LS state which is maximally...

In those kind of relative velocity questions in calculus & vectors class, does the direction of the plane need to be flipped when drawing the triangle to find the magnitudes and angles? Example of a question: An airline pilot has her controls set to fly at an air speed of 615 km/h at an azimuth...

A Ladder $13ft$ long is leaning against the side of a building. If the foot of the ladder is pulled away from the building at a constant rate of $\displaystyle \frac{2 in}{sec}$ how fast is the angle formed by the ladder and the ground changing in $\displaystyle\frac {rad}{sec}$ at the instant...

Hi, can I know what are the ways to show that the ground state particles of a Bose Gas possesses 0 entropy?

Homework Statement Consider a molecule with an electric dipole moment d. The Hamiltonian of a molecule in the external electric field E is: \hat{H} = \frac{\hat{L^2}}{2I} - dE \cos{\theta}, where the polar angle \theta characterises the orientation of the molecule. (We have chosen the field...

In the vertical jump, an athlete starts from a crouch and jumps upward to reach as high as possible. Even the best athletes spend little more than 1.00 s in the air (their "hang time"). Treat the athlete as a particle and let ymax be his maximum height above the floor. To explain why he seems...

The wave function of an electron in ground state hydrogen atom is non-zero at points far away from the nucleus. Interpreted as the probability of finding the electron, this is telling us that there is a finite probability of finding an electron far away from the nucleus even if it is at ground...

Why does Vanadium have a ground state electron configuration of 4s2 3d3 and not 3d5? In introductory chemistry and the latter arrangement seems to be lower in energy. Why is the former configuration the actual one?

In designing a circuit what point should I pick as the ground point? I know it's the reference node in schematic to calculate node voltages and could be anything, but when designing the PCB there should be a physical point that adhere to some conditions as I guess that make it a valid ground...

Hi, I've been working through my lecture notes from last year and I encountered this example of Russel-Saunders term symbols. I'm confused by the value of L being given as 1 + 2 = 3. What I recalled was that L is defined for two electrons by the Clebsch-Gordan series L = l(1)+l(2), l(1) +...

I take high speed videos of tennis strokes for analysis. One of the best and most informative camera vantage points for observing the tennis serve is from above the server. Here is an example of one of the rare high speed videos available taken with the camera above the server...