Box Definition and 1000 Threads

Homework Statement Suppose a particle is confined in one dimension to a region of width L. Obtain an approximate formula for its minimum kinetic energy. Homework Equations ΔxΔp ≥ h/4π The Attempt at a Solution 1. Put L in for Δx 2. Divide by L. It is positive 3. Δp ≥ h/(4πL)...

Homework Statement A box with a mass of 2.2 kg sits on top of another box with a mass of 3.8 kg. The coefficient of friction between the two boxes is 0.25, and the coefficient or kinetic friction between the larger box and the horizontal surface is 0.32. Determine the largest horizontal force...

Homework Statement A small box of mass m_{1} resting on a plank, of mass m_{2} and length L, which itself rests on a frictionless, horizontal surface. Both box and board are stationary when a constant force F is applied to the board. Take g to be the acceleration due to gravity and...

Whwn i am doing exercise, i don't know how to solve the follow question by myself Although i hv the ans, i want to complete it by myself. Plz give me some tips only so that i can finish this question, please also tell me how do you know the question should be solved in this way. The question...

I am trying to formulate a solution to the particle in a box energy eigenvalue problem, without solving a differential equation, instead using eigenvectors of p^2. My idea is to do this. Within the box (let's say it is defined between [-a,a] and within this region the hamiltonian is H={p^2}/{2m}...

Homework Statement A 19.0 kg box sits on a frictionless ramp with a 14.9° slope. The movers pull up a rope attached to the box to move it up. If the rope makes an incline with the ramp that is 42.0° to the horizontal, what is the smallest force F the mover must use to move the box up the...

Homework Statement A rigid thick walled insulating chamber containing a gas at a high pressure ##P_i## is connected to a large insulating empty gas holder where the pressure is held constant at ##P_A## with a piston. A small valve between the two chambers is opened and the gas flows...

Homework Statement At the bottom of a hill, a box has a speed of 15 m/s. The hill forms an angle of 30 degrees with the horizontal. How far up the incline of the hill does the box slide?Homework Equations My answer: d = (vf2 + vi2) / 2a The Attempt at a Solution vi = 15 m/s vf = 0 m/s a =...

What operator acting on the vacuum state (vacuum state of the box?) gives a m^3 box of cosmic background radiation at 2.7K? As the temperature 2.7K slowly drops (wait a million years) must our operator above change in time? Do photons scatter via gravitions so that their energy changes...

A cubic box of side a = 0.410 m is placed so that its edges are parallel to the coordinate axes, as shown in the figure. There is NO net electric charge inside the box, but the space in and around the box is filled with a nonuniform electric field of the following form: E(x,y,z) = Kz j + Ky k...

A 10.0-kg box is placed on top of the 19.0-kg box, as shown in the figure. Determine the normal force that the 19.0-kg box exerts on the 10.0-kg box. i know what the normal force of the 19 kg box. i am having problem setting these kind of problems.

Hi guys! I'm new here. Here is the problem, verbatim: Two people pull to the right on a box with forces of 100 Newtons at an angle of 60 degrees with respect to the x-axis into the first quadrant and 80 Newtons at an angle of 20 degrees down into the fourth quadrant respectively. A third...

Hi PF, I'm working on a problem for some guys and I need to add on to an existing machine. Attached is a back view of the machine (it's a drawing, sorry), there is a threaded rod that sticks out the back(white), attached to a motor at the bottom(black). There is a winged nut at the top of the...

https://www.physicsforums.com/attachments/1141 (a) I presume the frequency row has to equal 100 so $$k=100 - (26 + 10 + 20 + 29 + 11)= 4$$(b)(i) again presume the median is based on frequency and on ordered list so median of $4\ 10\ 11 \ 20\ 26\ 29 = \frac{31}{2}$ or $15.5$ (ii)...

Homework Statement Homework Equations \begin{align} \Delta p \Delta x &\geq \frac{\hbar}{2}\\ \langle p \rangle &= \sqrt{\langle p^2 \rangle - \langle p \rangle^2}\\ \langle x \rangle &= \sqrt{\langle x^2 \rangle - \langle x \rangle^2} \end{align} I allso know that a wavefunction of a...

Homework Statement A 15 kg block slides along a horizontal frictionless surface 3.0 m above the ground at a constant speed of 2.0 m/s. The block then slides down an incline that makes an angle of 35° with the horizontal and has a coefficient of kinetic friction equal to 0.30. After reaching...

The following diagram show a solid figure ABCDEFGH. Each of the six faces is a parallelogram The coordinates of A and B are A(7,−3,−5),B(17,2,5) $\vec{AB} = \langle 17-7, 2+3, 5+5 \rangle = \langle 10, 5, 10 \rangle$ $|AB|= \begin{align*} \sqrt{ (17 - 7)^2 + [2 - (-3)]^2 + [5 -(-5)]^2}...

The following diagram show a solid figure ABCDEFGH. Each of the six faces is a parallelogram https://www.physicsforums.com/attachments/1034 The coordinates of $A$ and $B$ are $A(7, -3, -5), B(17, 2, 5)$ a) Find (i) $\vec{AB}$ and (ii) $|AB|$ $\vec{AB}=A+B=(24, -1, 0)$...

Homework Statement For the ground state of a particle in a rigid box, we have seen that the momentum has a definite magni- tude (h/2π)k but is equally likely to be in either direction. This means that the uncertainty in p is Δp≈ (h/2π)k. The uncertainty in position is Δx≈ a/2. Verify that...

I desire to build a box that is sound proof that would be only slightly larger then my head, which I could scream as loud as I possibly could, yet the outside world would barely be able to hear, or not be able to hear at all (as little as possible). I have almost no knowledge of physics (only an...

My knowledge of Quantum Mechanics is not nearly as complete as may be needed to address this problem but I am still curious as to what would happen. As I understand it if we go along with the Schrodinger's Cat thought experiment we can say that the cat is in a state of superposition. And that...

So, in the topology text I'm reading is mentioned that if each ##X_n## is first countable, then ##\prod_{n\in \mathbb{N}} X_n## is first countable as well under the product topology. And then it says that this does not need to be true for the box topology. But there is no justification at all...

Hello, I've been working on some questions from Rice's Mathematical Statistics and Data Analysis and I'm not sure about my solutions. The question I'm working on is as follows: 1.8 #59c A box has 3 coins: 1 with two heads, 1 with 2 tails and 1 fair coin. A coin chosen randomly is flipped...

Homework Statement Calculate the surface temperature of a stainless steel junction box that is in a 35C ambient temperature environment. There are electrical "boxes" that generate 30W of heat inside of this box. Homework Equations (1) Q_dot_total = Q_dot_conv + Q_dot_rad (2) Q_dot_conv...

This is actually not a homework but it looks like one.So I posted here Homework Statement A rocket is pushing a box on empty space. The rocket is exerting a force on the blue colored box.In turn the box is exerting the same force on the rocket.The engine(or fire or whatever) it exerting a...

In one dimension the normalized momentum eigenstate for a particle with periodic boundary conditions of length L is: \psi_k(x)=\frac{1}{\sqrt{L}}e^{ikx} . Is the completeness relation obvious: \Sigma \psi_k(x)\psi_{k}(0)=\frac{1}{L}\Sigma e^{ikx}e^{-ik0}=\frac{1}{L}\Sigma e^{ikx}=\delta(x)...

Homework Statement A frictionless, incline plane at 20 degrees has a spring with force constant k=500N/m attached to the bottom, parallel to the inclined plane. A block of mass m=2.5kg is placed on the plane at a distance d =3m from the spring. From this position the block is projected...

Homework Statement You place a 2kg box against the side of a cart. Nothing is used to stick the box to the cart which accelerates to the right. The coefficient of static friction is 0.6. Find the minimum acceleration of the cart needed so that the box does not fall Homework Equations...

Homework Statement We have a homogenous box on a surface with static friction μ=0.5. We apply a force on the top of the box at an angle 30 degrees to the horizontal (see picture) and we want to know for what values of P does the box slip and tip. I have drawn a free-body diagram here of the...

Homework Statement I think this is a very easy problem, I will try to show you guys what I tried to come up with: A particle is in an infinite potential box and is described in a certain moment of the normalized wavefunction ##\psi(x)=\sqrt{\frac{8}{3a}}sin^2(\frac{\pi x}{a})## for (0<x<a)...

I have been thinking about it for sometime but couldn't really get the answer. This is the progress I have made till now. E |ψ> = H |ψ> E <p|ψ> = <p|H|ψ> Now how to evaluate the number <p|H|ψ>? Although I can evaluate this number by introducng identity operator 1 = \int|x><x| dx. But for...

Homework Statement A particle of mass m is inside a 1 dimensional "box" of length L such that it's restricted to move between ##x=-L/2## and ##x=L/2## where the potential vanishes. 1)Determine the eigenvalues ##E_n## and the eigenfunctions ##\psi _n## of the Hamiltonian imposing that the...

I'm working with clathrate compounds in a glove box filled with Argon. My problem is that there always remains a small amount of oxygen in the glove box even after multiple purges. This oxygen binds and makes an oxide layer on my clathrates. I don't know how to avoid this and am trying to find...

In an exposition about the modal logic system K4, after introducing the box "necessity" quantifier \Box (where \BoxP is essentially that the Gödel number of P is provable), then introduces the "strong box" quantifier [s] (I don't know how to put an s inside a box in LaTex) as: [s] A = A \wedge...

Homework Statement There is a sheet of metal 30 x 12 inches long and you want to make a box by cutting x by x corners out at each corner of the sheet metal. (x will then be your height) The box will have no top to maximize volume. What is the maximum volume and what are the side lengths...

Hey! I need some help at the following exercise... We have a box with balls and 10% of them are red. If we choose at random 20 balls with replacement, which is the probability to pick more than 3 red balls? Thanks in advance!

I'm not sure I know all that I should to understand it. I'm posting to try and determine if I do. Knowing what I know, however, it seems unnecessarily confusing. Almost all students I talk to agree. Why not just call it a particle on a line segment? Or just moving in one dimension?

Finding acceleration of box-- given mass of box and magnitude of frict Doing homework and stuck on this question. A student pushes a 10kg box and let's it slide across the floor. The magnitude of the frictional force acting on the box is 40 N. What is the acceleration of the box? Relative...

Homework Statement A particle is in the first excited state of a box of length L. Find the probability of finding the particle in the interval ∆x = 0.007L at x = 0.55L. Homework Equations P = ∫ ψ*ψdx from .543L to .557L The Attempt at a Solution Normalizing ψ gives ψ=√(2/L)sin(nπx/L)...

Homework Statement 3 Forces/vectors in a box going from a corner. F1=260N F2=75N F3=60N then it says calculate F0 which is F0=F1+F2+F3 problem is that the answer is not the sum of the vectors its 347.3N its also wants the angles of the vectors to the corner problem is no cordinates are...

Homework Statement Find the energies of the second, third, fourth, and fifth levels for the three-dimensional cubical box. Which are degenerate? Homework Equations E = h^2/8mL^2 (n^2 sub x + n^2 sub y + n^2 sub z) The Attempt at a Solution The levels would be degenerate if one of...

Homework Statement So in the future, I will have to find out what is inside a black box: Homework Equations The Attempt at a Solution Here is the solution to it: http://drunkenengineer.tripod.com/Year1/ele202/blackbox/blackbox.html The issue is that I'm having trouble understanding why the...

I'm trying to find the energies for n levels of a 3D cubical box. Is there a general equation for this?

I did some quick searches and couldn't find what I was looking for. I found plenty of project boxes, but I didn't find any project boxes with a breadboard combination for sale. I just need to make a circuit inside of a box using capacitors or inductors. Very simple but it has to look...

Homework Statement Three particles, each of mass m, reside in a 1D "box" of length L. Find a complete set of wavefunctions,\phi_{k}(x) for the system. In this sense, "complete" means that any state of the system,\psi(x) can be written as a superposition of the wavefunctions...

It's said that it is not possible to tell the difference between acceleration of objects within a closed box and acceleration due to gravity. Is this allways the case.Does the acceleration of objects within a closed box act uniformly or does this depend on the gradual acceleration of the...

Homework Statement Estimate to the nearest degree, the angles that a diagonal of a box with dimensions 10cm x 15cm x 25cm makes with the edges of the box.Homework Equations cos\theta =\frac{u\cdot v}{\left \| u \right \|\left \| v \right \|}The Attempt at a Solution For the angle between the...

Homework Statement An eletron is moving along one axis between x=0 and x=L. It's mass is given by m. We want to know the energy and wave function of its possible states given by the quantic number n. Show that the solution to the above equation is En=n^2*h^2/(8*m*L^2)...

A box of mass 5.0-kg is accelerated from rest across a floor at a rate of 2.0m/s^2 for 7.0s. Find the net work done on the box? W=Fd

If a force is applied to a box, and the box is not displaced, no work is done on the box, right? But to apply the force, don't you use up calories which is a unit of energy?