Box Definition and 1000 Threads

I have read that electric field at any point( not only at center) inside a uniformly charged spherical shell is zero(by symmetry). But if we take a uniformly charged cubical box, will electric field be zero at every point inside the box? I am confused please help ( I think it should not be zero...

Homework Statement If m=5.0kg, φ=30◦ and μs =0.87, what is the minimum force needed to make the box slide down the slope? [/B] Homework Equations force of status friction is less than or equal to the normal force multiplied by the coefficient of static friction F,normal=mgcosφ The image...

If correct, Uzan refutes Popescu and Rohrlich. To me this seems like a big deal. Super-Quantum, Non-Signaling Correlations Cannot Exist Pierre Uzan http://arxiv.org/abs/1602.01135 Comments?

I put a light bulb inside a box and make it glow, is there a way to know where the light bulb is if the box is closed and not transparent

Homework Statement a 0.60 kg mass is attached to one end of a 1.7 m string. The string will break if its tension exceeds 60 N. The mass is whirled in a horizontal circle on a frictionless tabletop, such that the other end of the string remains fixed at the axis of rotation. What is the maximum...

Homework Statement Homework Equations ΣFx=max The Attempt at a Solution I drew a free body diagram for the box and set up the equation to solve for θ, but I'm not sure how to do it without μ

Hello everyone! Does anyone know if there is a know expression for the Green's function for Poisson's equation that vanishes on an ellipse in 2 dimensions? I'm essentially looking for a solution to: $$ \nabla^2G(\vec x-\vec x_0)=\delta^2(\vec x-\vec x_0) $$ in 2 dimensions where $$G(\vec x-\vec...

I'm trying to understand the meaning of kT (energy) in molecular systems, how to define the temperature of an individual molecule, and how a molecule receives thermal energy or dissipates thermal energy. Here is my 'gendanken': One molecule is floating in a box, in vacuum. The temperature of...

Homework Statement A box of kiddimix contains 20 chocolates of which 8 are plain chocolates and 12 are milk chocolates. If 16 of the 20 have soft-centres, what can you say about how many plain chocolates there are with soft-centres? Homework Equations You can say there are 8/20 plain...

Homework Statement Two particles of mass m are placed in a rectangular box with sides a>b>c (note 3D-box). The particles interact with each other with a potential V=A\delta(\mathbf{r}_1-\mathbf{r}_2) and are in their ground state (1s). Use first order perturbation theory to find the systems...

I want to do an experiment where I follow the particle in all trajectory until it hits the wall of the box, then I want to draw out this box's structure based on the particle collision. One thing would be that the particle does not need to go in all trajectory, but I would like to know how to...

Homework Statement [/B]Homework Equations E(p)=mgh W = Fs 3. The Attempt at a Solution The book says the crane does mgh amount of work, while gravity does -mgh. What I don't understand is, for the box to be lifted up, doesn't string tension force have to be bigger than gravity - or else it...

1. A box of mass m = 59.0 kg (initially at rest) is pushed a distance d = 83.0 m across a rough warehouse floor by an applied force of FA = 204 N directed at an angle of 30.0° below the horizontal. The coefficient of kinetic friction between the floor and the box is 0.100. Determine the...

Homework Statement person and a box of equal masses are hanging off of the same pulley. The rope is considered massless. The person and the box are separate from each other. (The person is NOT standing on the box.) Homework Equations How far does the box move if the person starts climbing...

Homework Statement An electron in a one-dimensional box with walls at x =(o,a) is in the quantum state psi = A o<x<a/2 psi = -A a/2<x<a A) obtain an expression for the normalization constant, A. B) What is the lowest energy of the electron that will be measured in this state...

Hi, I am wondering about additional solutions to the particle in a box problem. In the one dimension the wave functions allowed all make sense with nodes pinned to an infinite potential barrier at either end and then divided into node increments related to the length of the box. However, in 2...

Hi. I am just starting to self-study QFT. Have been looking at the non-relativistic case of particles in a box. Have come across creation operators in the occupation number representation which create a particle in specific momentum state. But I thought in a rigid box there are no momentum...

Homework Statement A box of mass m = 40kg is released from rest at thte top of a frictionless ramp. The ramp makes an angle theta = 45 degrees to the horizontal. After sliding fom the rigin a distance d = 2.00 m down the ramp, the box strikes a spring of force constant k = 500 N/m. The box...

Homework Statement At a construction site, a 62.0 kg bucket of concrete hangs from a light (but strong) cable that passes over a light friction-free pulley and is connected to an 80.0 kgbox on a horizontal roof (see the figure (Figure 1) ). The cable pulls horizontally on the box, and a 50.0 kg...

Homework Statement A 100N box is initially at rest on a rough horizontal surface. The coefficient of static friction between the box and the surface is 0.6 and the coefficient of kinetic friction is 0.4. A constant 35N force is aplied to the box horizontally. Identify from choices (a) - (e)...

Homework Statement A force F pushes two boxes, box 1 and box 2 up an inclined plane of 30 degrees. If F=25 N and box 1 is 2 kg and box 2 is 3 kg, what is the force exerted on the 2 kg box by the 3 kg box. Assume no friction. Homework Equations F=ma. The Attempt at a Solution Since the...

Homework Statement 1000 neutral spinless particles are confined in a one-dimensional box of length 100 nm. At a given instant of time, if 100 of these particles have energy 4ε0 and the remaining 900 have energy 225ε0, then the number of particles in the left half of the box will be...

Homework Statement A One dimensional box contains a particle whose ground state energy is ε. It is observed that a small disturbance causes the particle to emit a photon of energy hν=8ε, after which it is stable. Just before emission a possible state of the particle in terms of energy...

According to standard cosmology theory the physical momentum p of both massive and massless particles decay like: $$p \propto \frac{1}{a(t)}$$ where a(t) is the scale factor as function of cosmological time t (for a derivation see page 12 in the following lecture notes...

Homework Statement An electric motor is used to pull a 125 kg box across a floor using a long cable. The tension in the cable is 350N and the box accelerates at 1.2m/s2 (forward) for 5.0s. The cable breaks and the box slows down and stops. Calculating the coefficient of kinetic force? Given...

Homework Statement I was wondering about how the placement of weight affects Soap Box Cars. I have been racing them for 5 years now, and I cannot find any information. I was wondering if there was a formula to find the relationship between speed and weight, and how to solve it. For instance, if...

Dear all,i have recently been provided a task of designing a basic gear box for a vehicle having following engine specifications: 127cc, max torque: 7.8N-m Max. RPM: 3200 How do I proceed for this? Please guide me what all additional information is required for this calculation and what all do...

Homework Statement A box of m= 25 kg is pulled by a rope with a force of tension, F = 40 N inclined at an angle of 30o with the horizontal, there is no friction between the box and the ground. b) Determine the acceleration of the box. c) Write the equation to find the acceleration of the...

Homework Statement The diagram shows a box with parallel faces. Two of the faces are trapezoids and four of the faces are rectangles. The vectors A, B, and C lie along the edges as shown, and their magnitudes are the lengths of the edges. Define the necessary additional symbols and prove...

Homework Statement The velocity of a conveyor is V=30+0.1t2. a box of mass m=3[kg] falls from zero height at t=0. the kinetic coefficient of friction is μk=0.4 and the static is μs=0.5. 1) At which times the friction is kinetic and at which static 2) What's the box's velocity in the different...

I am applying for a PhD program in statistics and I want a full assistantship. Should I check the box to apply for additional financial aid or will that affect an assistantship chance? Thanks.

Hi. Assume we have a large number of identical boxes of some finite length ##l## and with infinite potential walls. Let's prepare them all in the same momentum eigenstate. Since for eigenstates ##\Delta p=0##, by the uncertainty principle ##\Delta x## should go to infinity. However, since the...

I know its written in greek but i think its a common problem...any ideas? i think that's why the "build 7061" geniunity problem appears. :(

hi, This is probably very simple issue, but i am not an engineer nor have an understanding of basic physic... I need to calculate if the tape used to connect (sealed) to ends of the cardboard box will withstand the weight of the product i put inside it. I have a tape properties (tensile strength...

This is mainly just a theoretical question: say you have a rectangular box made of styrofoam (one of those ice cooler things) and it is levitating in air at room temperature conditions. It also has one hole at the top of the container so that heat can get out of it. Inside the box is a lightbulb...

For particle in a box with the finite depth, is it traveling wave? or standing wave? I am confused with its ability to pass through the potential walls that is classically forbidden area which makes me think it is traveling wave. But for particle in a box with infinite potential, I understand...

Homework Statement A 90 kg box is pushed by a horizontal force F at constant speed up a ramp inclined at 28°, as shown. Determine the magnitude of the applied force. when the ramp is frictionless. when the coefficient of kinetic friction is 0.18 Homework Equations F=mg FN=mg μ= Fk/FN The...

Homework Statement A small ball has mass 3.4x10^-8 kg and charge of 2.0x10^-5 C. It enters a box with initial speed 1.2x10^4 m/s. The point where the charge leaves the box is at a voltage 350kV higher than the entry point. Find the speed of the ball as it leaves the box. [/B]Homework Equations...

Hi, in case of a particle inside a box (infinite square well), can degeneracy occur for different energy eigen states? please explain...

If I have a large steel box that is 27ft x 8ft x 8ft and has 7 in thick walls with 4 non-insulated windows each 1ft by 1ft, where does heat escape from inside the box, is it the windows and the walls? So if the inside temperature needs to be 72 F and the outside air is 0 F how much heat would...

Homework Statement a match box consists of an outer cover, open at both ends, into which slides a rectangular box without a top. The length of the box is one and a half times its breadth, the thickness of the material is negligible, and the volume of the box is 25cm^3 . If the breadth of the...

hello I have a liquid or gas inside a metallic box (eg. stainless steel 5mm thick) how can I increase its temperature without heat convection or conduction?

Hello. I've recently have a lot of question of building Faraday cage for our high voltage gas discharge lab. I think this question is a kind of fundamental question for such a job. Let's say I would make perfect Faraday cage with perfect shielding or have metal plate of infinity transverse...

Homework Statement An ant which can crawl along the walls of a cubical box of side 1 m can travel from one edge to the diagonally opposite edge by traveling what shortest distance? The options are : a) 2m b)√2 +1 m c) √3 m d) √5 Homework EquationsThe Attempt at a Solution I drew a...

Homework Statement A stationary 10 g box is pushed with a force 20 Newtons across a level floor. How long will it take the box to reach a wall 10 meters away? Homework Equations Applied force - Friction Force? The Attempt at a Solution I am unsure how to attempt this. Do I need to know the...

Homework Statement A loaded penguin sled weighing 75 N rests on a plane inclined at angle θ = 21° to the horizontal (see the figure). Between the sled and the plane, the coefficient of static friction is 0.30, and the coefficient of kinetic friction is 0.18. (a) What is the minimum magnitude of...

I've put a small battery powered commercial radio inside a Quality Street tin. The tin is all metal with rolled joints and the lid is a tight fit. I'd be willing to bet that there are no holes greater than 0.1mm around the lid's closure. Why does the radio work when receiving an AM station (1...

Suppose we have a 3D potential box having different length. Now suddenly we double the length of a particular side(Say along X direction) of the box. Can we calculate what will be the eigen function of the Hamiltonian. Is there Time Independent S.E. holds?

Homework Statement How far will a box slide if its initial velocity is 1.5 m/s, kinetic friction is 0.15 and the object is 30 kg Homework Equations a= (kinetic friction)(acceleration due to gravity) and V(final)^2 - V(initial)^2 = 2(a)(D) The Attempt at a Solution a= 0.15 x 9.81 m/s^2 =...

Homework Statement A truck is moving at constant velocity v0 with a box of mass m on it. Suddenly it starts decelerating until its velocity becomes zero. Between the box and the truck the is a force of friction and the deceleration of the truck is sufficiently slow to allow the box not to start...