Ground Definition and 945 Threads

Homework Statement A hot-air balloonist, rising vertically with a constant velocity of magnitude v = 5.00 m/s, releases a sandbag at an instant when the balloon is a height h = 40.0 m above the ground. After it is released, the sandbag is in free fall. For the questions that follow, take the...

Homework Statement A ball is tossed up into the air. It reaches maximum height and comes back down. What is the net force on the ball at the following situations: a. The ball is moving upward as it is released. b. The ball is at it's highest point. (when it comes to a stop i suppose)...

A little plug for my supervisor and former group. After a couple of years work with a very clever (zero read noise) CCD and a bit of clever DSP programming they now have a system which takes a sequence of very short exposures, picks the ones in which the atmosphere is frozen to give an...

Hi Members I am preparing to do a presentation on possible research opportunities in ground penetrating radar before an Industry and academic audience. Anyone with information as to what is lacking or needs improvement in current BH or GPR research in the context of Data analysis (processing...

Hey! I know that with option A I have an always-open-line and no problems in communication... What I would like to know is, if option B will work when the ground is the building ground? Liad.:)

Homework Statement V(x) = k|x|, x \in [-a,a], V(x) = \infty, x \notin [-a,a]. Evaluate the ground state energy using the variational method. Homework Equations a = \infty and \psi = \frac{A}{x^{2}+c^{2}}. The Attempt at a Solution 1 =...

Hello there I'm currently working on an EM device that should be able to measure the humidity in the ground. I cannot give too many details, but let's consider the following issue: I have a copper closed loop in which I send some current to generate a magnetic field. But there are some EM...

There are a lot of people with a lot of different views and opinions around the world supporting themselves with various real and/or fictive data, graphs and predictions. Some of them are qualified and some are not. Others questions what difference qualification makes. Some has a clear political...

My professor decided to throw us a curveball to try and solve the following problem: A third baseman makes a throw to first base 38m away. The ball leaves his hand with a speed of 36m/s at a height of 1.7 meters from the ground and making an angle of 14 degrees with the horizontal. a)...

We are using 120V commercial grade electronic ballasts, properly grounded, rated at 2Amps to drive two low pressure UV lamps submerged in water rated at 800mA. System requirements are to use GFI barkers with each ballast. This installation in a wastewater treatment plant, where there are...

Homework Statement http://img253.imageshack.us/img253/4648/untitledfn3.jpg The Attempt at a Solution I've done parts a and b succesfully, but am not sure how to do c. :confused:

Homework Statement dan is gliding on his sb at 4m/s. he suddenly jumps backward off his sb, kicking the sb foward at 8m/s. how fast is dan going as his feet hit the ground? dan's mass is 50kg and the sb's mass is 5kg Homework Equations The Attempt at a Solution

Is the ground state of the infinite square well an eigenfunction of momentum?? If so, why. If not, why not??

i'm trying to figure out how much force it would take to remove a three inch piton driven into rock or concrete. For example, assuming the concrete in a 50 square foot parking lot was more than three inches deep, and you drove a 3 inch piton into the center of it, how many pounds of force would...

I am looking at a diatomic molecule where the Hamiltonian is given as H = l²/2I + F*d*cos theta where d is the dipole moment. The term F*d*cos theta is small. I write the energy of ground state as E_0 = \hbar*l*(l+1)/ 2I Than I have to determine how much the ground-state energy...

Homework Statement A baseball is hit at ground level. The ball is observed to reach its maximum height above ground level 3.0 s after begin hit. And 2.5 s after reaching this maximum height, the ball is observed to barely clear a fence that is 320 ft from where it was hit. How high is the...

I'm working all alone with nobody to help me, and now I'm stuck! :( I'd really appreciate it if you could help me out. I'm working with the ground state of the one electron hydrogen atom. Trying to determine the radial dependence on probability density. It should only depend on the radial...

Consider a helium atom where both electrons are replaced by identical charged particles of spin-1. Ignoring the motion of the nucleus, the Hamiltonian is [see attachment 1] Construct an energy level diagram ( qualitatively ) for this "atom", when both particles are in the n=1 state, and...

Hello. I'm trying to grasp this concept. The question states: An excited atom decays to its ground state and emits a photon of green light. If instead the atom decays to an intermediate state, what color of light might be emitted? I have the electromagnetic spectrum with the visible lights...

A particle in a potnetial V(x) has a definite energy E = - \frac{\hbar^2 \alpha^2}{2m} and its eigenfunction is given by \psi(x) = Nx \exp(-alpha x) if 0 <= x < infinity zero elsewhere Prove that V(x) = -alpha \hbar^2/mx 0 <= x < infinity infinity elsewhere Given that the...

I've been told (in class, online) that the ground state of the 3D quantum harmonic oscillator, ie: \hat H = -\frac{\hbar^2}{2m} \nabla^2 + \frac{1}{2} m \omega^2 r^2 is the state you get by separating variables and picking the ground state in each coordinate, ie: \psi(x,y,z) = A...

can someone help me with this problem? I am not sure where to start from. if someone can give me some advice. While driving north at 25 m/s during a rainstorm you notice that the rain makes an angle of 38 with the vertical. While driving back home moments later at the same speed but in the...

if you spin a powerball in the shape of a cone it will reach 13000 rpm the idea is to nail a giant powerball to the ground at latitude 45º so it describes a cone and steal little by little Earth's angular momentum to generate energy do you think this is viable?

H=\frac{p^2}{2m'}+V_0(r)+V(r) where V(r)=2[3\frac{(S \cdot r)^2}{r^2}-S^2] and V_0(r) is a rotationally invariant potential, p=p1-p2, the relative momentum and m' the reduced mass. S=S1+S2 spin operator. Assume first that V(r) is zero; what is the degeneracy of the ground state...

Can someone explain to me why the ground state energy of a free electron fermi gas is not just: E = 2 \int_0^{k_f} \frac{\hbar^2 k^2}{2m} 3k^2 dk Where the factor of two is due to the fact that there are two electron states for each value of k. The idea is to add up all the energies of...

Hi everyone. I am doing research for a technical analysis study, and I need a little help. What determines the amount of "bounce" an objects creates when it hits the ground? Now, this object is a perfect shape hitting a even floor, so the angle should have nothing to do with it...

A pile driven into ground using a hammer question! Hi all, I have been attempting the following question, could you check my answers /method please :) A pile is driven into the ground by a hammer of mass 500Kg's dropped from a height of 4 meters. The mass of the pile is 40Kg's and the...

The height of an object above the ground at time t is given by s = v0t - (g/2)t2 where v0 is the initial velocity and g is the acceleration due to gravity. (a) At what height is the object initially? (b) How long is the object in the air before it hits the ground? (c) When will the object...

dear friends i have a problem in physics please solve it it is that a man covers 100 m distance by running...so calculate the total time by that he was in contact with the groung and the time that the time he remain in the air... numerically d=100m t(on the ground)=? t(in the air)=...

Erik Drops a ball from a height of 15.0m above the ground. After it hits the ground it only bounces back up to a height of 13.5m. Erik Catches it at this point, as it is just about to fall back down. just need some quick helping steps to get me started on these questions help would be...

which drop of water has more "force" to hit ground? wish to know which drop of water has more "force" when hitting ground? http://img93.imageshack.us/img93/9831/image20nh.png and perhaps some "simple" explanation why you think so. thank you :)

This is my second post concerning a question I had from Hawking book. I am completely new to this subject, and lack the mathematical background necessary to fully understand these concepts, but I hope that by posting my question I will at least not be so confused about it after receiving some...

hi can anyone please help me I came across this statement "Since we only consider the electronic ground state of the system, there can be no net force or torque acting upon the subsystem of classically behaving nuclei". Can anyone explain what this means?

Occams razor and logic implies that there has never been nothing, so why back ground independance ?

What is the ground state energy of the following. (a) an electron Well the formula is: E_n = (h^2/(8*m*L^2))*n^2; The ground state means, n = 1, its the lowest enegery level possible. So i plugged in n = 1, mass of e = 9.11E-31; h = 4.136E-15 eVs; L = 100 pm, because the book says that's...

Im doing a mobile device and i want to create a floating ground but I've no idea how to do it or even if its possible. the catch is that it also functions as a excess current channel from a current limiter circuitry included. thanks for any advice.

A particle has mass 'm' and potential V(x) = x^2. Find the ground state of this wavefunction. Should I use the Hamiltonian operator here?

I need some help with this mechanics question please, A ball is thrown vertically upwards with speed 10ms/s from a point 2m above horizontal ground. a) calculate the length of time for which the ball is 3m or more above the ground. b) calculate the speed with which the ball hits the...

Hello everyone, I just started physics a few days ago (with 0 prior experience) so I'm still queasy with this stuff. If anyone could help me with this problem, I'd really appreciate it. Say I drop an object from a height z0. How long does it take the object to reach the ground? There are two...

I have this problem to do for homework for my physics class and I don't even know where to start! Could someone try to give me clues? The problem is: A pilot flies horizontally at 1300 km/h, at height h= 35 m above initially level ground. However, at time t = 0, the pilot begins to fly...

Person A: Falling from the top of a 20' ladder. Or Person B: Falling with a 20' ladder that is falling over. (from the top) Give me your answer and tell me why? This one is driving me crazy!

Hello I had a debate on comparing walking on the ground with velocity V and wlaking on an electrical walker with the same velocity V. My claim is that there is no difference between walking on the ground in velocity V and walking on an electrical walker with the same velocity V, in terms of...

My question is, derive an equation to find the maximum range of a projectile that's not on level ground. I am lost and i did attempt this, by making a diagram and subbing in what i thought i would need to use, but i still have not come up with the answer. please help

how can you measure the speed of the plane from the ground. Can anyone help and please explain as much as you can and if you can provide the equation/example that would be wonderful.?

The figure shows a bicycle wheel resting against a small step whose height is h = 0.110 m. The weight and radius of the wheel are W = 29.0 N and r = 0.350 m. A horizontal force F is applied to the axle of the wheel. As the magnitude of F increases, there comes a time when the wheel just begins...

Hi All Suppose we have a rectangular pool filled with water. But the concrete ground of this pool is substituted by a rubber sheet, resistent obviously to the weight of the water inside the pool. Now consider we produce a plane wave traveling along the greatest dimension of this rectangular...

According to a recent statement by general George Casey, senior military commander in Iraq, There is currently only one Battalion of Iraqi soldiers currently prepared to do "stand alone" operations. I find that a bit odd considering that Casey had said in June that there were three...

The paper delivery boy tries to throw the paper into your narrow driveway without slowing down. His pickup truck travels at 5.00 mph, and he throws the paper at 16.0 mph just as the truck passes the driveway. in what direction should he throw the paper in order for it to land in the driveway...

I'm a computer programmer, but I'm having trouble with this one. I need help figuring out how to calculate a 3D velocity vector which will make a projectile follow an ARC between two points on the ground, firing with a fixed speed. I have a cannon at point a (x, y, z) I have a target on...

Has anyone ever set off a really big professional-grade star burst style firework on the ground, in a desert somewhere? Maybe at the Burning Man festival? I am thinking you could stand within 30 feet of the epicenter in a plexiglass enclosure, with ear protection, and be unharmed. What...