Wall Definition and 756 Threads

E is finite and V is infinite, So T should be negative infinite

Hi all, this is a problem with which I led myself in circles with for hours, because I kept forgetting to factor in a different thing each time. Long story short, I thought I'd cracked it, but my answer and the given answer are out by a square. Please see my efforts below! Homework Statement...

Velocity Calculation -- ball bouncing off a wall at an angle Question: "A ball is locked at 45 degrees towards a wall at 4 m/s. It bounces away from the wall at an angle of 45 degrees at 3 m/s. Find the change in velocity of the ball at the bounce." My attempt: So I know that change in...

Ok, so I have completely *solved* this problem. What I mean is that I have attached the problem in a photo, and my work in a separate photo. My first answer was 62.2° and I did not round at all, I left all of the answers in my calculator. I rounded some on the second time through and got my...

Hi! If the atom is mostly empty space, why isn't it possible to walk thru a wall? The science documentary I saw the other day told me that if you where in a church, the nucleus itself would be represented by a fly on the floor while the electrons would be encircling the church cealing...

Homework Statement A uniform ladder of weight (W) is leaned across a rough wall and on a rough floor. The reaction at the wall is (S) with frictional force (G)(upward direction) while the reaction at the floor is (R) with frictional force (F)(away from the wall direction). Frictional forces...

When do you hit "the wall"? Hey all, I am currently in my first year of undergraduate degree on a software development BSc and am studying a quite introductory mathematics course which effectively only goes up to higher algebra and trig/geometry. Most of the course is self taught from...

Hello When a mechanical wave gets reflected from a rigid surface,say a fixed end of a rope ,it undergoes a phase shift of ∏ ,but when a sound wave gets reflected from a hard surface ,say from a wall,it doesn't undergo any phase shift . There is confusion regarding phase shift of sound wave...

This is my first forum post so I apologize in advance if I do not provide enough detail, speak clearly enough, or violate some forum etiquette. I have a few questions here all relating to the same thing so hopefully this isn't worded poorly or too much. When light strikes a surface, the...

Homework Statement See the attached picture Homework Equations The equations given should be the relevant ones. The Attempt at a Solution I feel I got a bad intuition and understanding of this problem. I could eliminate T in favor of S and then express x and T by U and S. Is this...

Homework Statement A ball is being pulled by a force given by ##F=kv^2##. Where "k" already includes the mass of the ball. After 10m it will run into a wall. The initial speed is 1m/s and there are no other forces involved. How much time does it take for the ball to hit the wall? Homework...

Homework Statement 32) The change in momentum, in kg m/s, that occurs when a 1.0 kg ball traveling at 4.0 m/s strikes a wall and bounces back at 2.0 m/s is A) 2. B) 4. C) 6. D) 8. Answer: C Homework Equations Momentum==Mass*Velocity The Attempt at a Solution I get...

Homework Statement Hi guys, I have a problem here. A man is sitting on a chair leaning at 60 degrees against a friction-less wall. The height of the chair is 1.20 meters and the distance between the man's center of mass and the wall is 0.5 meters. The distance between the guy's...

Homework Statement I have a wall, which is basically a gate of a shipping lock. I have different water levels on both side of the wall. I made a graph to illustrate my problem and dimensions: https://dl.dropboxusercontent.com/u/47965009/problem1.png Homework Equations 1. Find the...

Homework Statement Assume a shear flow against a wall, given by U= Uo (2y/ax - y^2/((ax)^2) where a is a constant. Derive the velocity component V (x; y) assuming incompressibility. Homework Equations Haven't been able to find any in my course notes. The Attempt at a Solution...

Homework Statement You are kicking a ball in the air that is sitting on the ground. You are told the initial velocity and the distance to a wall of a known height. To find out if the ball goes over the wall, you need to A) determine if the ball is going up or down when it reaches the...

Homework Statement Albert is pushing a 1.8 kg book against a vertical wall at an angle of 30.0 degrees. If the coefficient of static friction is 0.47 and kinetic friction is 0.35, how hard does Albert need to push the book to allow it to slide down the wall at a constant speed? Homework...

Homework Statement A sound source, detector and a movable wall are arranged as shown in the figure. In this arrangement detector is detecting the maximum intensity. If the speed of sound is 330 m/s in air and frequency of source is 600 Hz, then find the distance by which the wall should be...

What is the relation between the pressure that is exerted on the internal walls of a cylinder and the characteristics of a flow of water running inside it? Let's assume that the flow velocity is constant and that we have an inviscid flow of pipe flow type. Furthermore let's assume that the...

Homework Statement Above you had a ball traveling horizontally at 25.0 m/s bouncing off a brick wall and rebounding at 20.0 m/s. The ball was in contact with the wall for 3.50 ms, and you found the magnitude of the average acceleration during the time the ball was in contact with the wall...

Homework Statement Suggest a hypothesis to explain why algal and plant cells have cell walls. Suppose that mutant individuals from each group lacked a cell wall. How could you use these individuals to test your hypothesis? Homework Equations There aren't really... The Attempt at...

Hello, As we know, if one turn a light blub(and no other light is present) on and put his hand in front of a wall to make a shadow, the shadow is blurry, depending on the distance between the hand and the wall. I want to ask you if this blur is caused by quantum uncertenty (like this...

A smooth circular cylinder of radius b is fixed parallel to a smooth vertical wall with its axis horizontal at distance c from the wall. A smooth uniform heavy rod of length 2a rests on the cylinder with one end on the wall in a vertical plane perpendicular to the wall. Show that its inclination...

Homework Statement A uniform strut of length, L and weight 780 N is free to pivot about point P where it is attached to the wall (see diagram) A weight W = 815 N hangs straight down from the end of the strut. A rope is attached to the same end as the load and the wall completes the support as...

Circular Motion and Static Friction Problem.. "The Wall of Death" ride Homework Statement A fairground ride called "The Wall of Death" consists of a cylindrical container of internal diameter 6.50m, mounted on a cylindrical axis. The passengers feel as if they are being pushed against the...

[b]1. A 5kg block is held at rest against a vertical wall by a horizontal force of 100 Newtons. 1-What is the frictional force exerted by the wall on the block 2-What is the minimum horizontal force needed to prevent the block from falling if the static coefficient of friction between the wall...

Homework Statement I´ll show it with a picture: Homework Equations Static equilibrium, Sum Forces=0 ; Sum Moments= 0 The Attempt at a Solution With the Fx, and Fy equations I can calculate the reactions Rx and Ry but I don´t understand the moments equation: Sum M around...

A lot of you seem like the "handy" type so maybe you can give me some advice. A friend of my had some acoustic foam on his wall (with spray-on adhere stuff), removed the foam, and now some foam is stuck and in other spots some of the paint was removed. 1. How should I remove the remaining...

cylindrical pressure vessel with inner pressure P. Take a infinitesimal cube on the inner-wall of the vessel. When calculating the normal stress along the radial direction it is assumed that that it is equal to P on the both the negative \widehat{r} and positive \widehat{r} directions...

Came across some rather [to me] incredible views of some large scale structures our universe...Check out the large graphic here: http://en.wikipedia.org/wiki/Galaxy_filament and if interested, also click on the additional illustrations just below...

Longtime lurker here. I want to put some science posters on the wall, but am not sure which firms send these out for free. I'm talking about the posters with some sort of diagram or schematic, in color. I've only found one organisation that sends them out. And I'll only name it if...

I have a 36" OD aluminum drum within another 48" OD aluminum drum creating 6” channel between the two diameters. The total height of the drum assembly is 16” This design project that I am working on requires me to fill this channel up with 12” of water which equates to about 342.5 lbs of water...

Homework Statement You throw a snowball at 0.0 Celsius at a brick wall. If you want it to melt completely, how fast will you have to throw it? Homework Equations Q = mL E_k = \frac{1}{2} mv^2 The Attempt at a Solution I initially reasoned that you would use Q = mL to find the energy...

The problem is from the MIT Open CourseWare Calculus eBook by Strang. Chapter 12.2, #3: A ball is thrown at 60 degrees with initial velocity of 20m/sec to clear a wall 2m high. How far away is the wall? Finding flight time T, range R, and max height Y(max) is the easy part. How do I find...

Homework Statement The questions states, "If you speak while standing in a corner with your face toward the wall, you will sometimes notice that your voice sounds unusually loud. Explain."The Attempt at a Solution Is this because the sound waves are bunched up when they bounce off the corner...

1. Homework Statement During a tennis match, a player serves the ball at a speed s, with the center of the ball leaving the racquet at angle θ below the horizontal at a height y0. The net is a distance d away and has a height h. When the ball is directly over the net, what is the distance...

Homework Statement I'm only interested in the second part where V << v Homework Equations Energy The Attempt at a Solution First I boosted to the frame of the moving wall to find the change in velocity of the ball after a collision with it. In the frame of the moving wall...

Homework Statement rectangle wall with 3m height, 20 length, 6.0m width. Rectangle filled with water. The Attempt at a Solution I've calculated the force acting on the wall to be: 1766 KN I have a hydraulic ram exerting 5 tonnes of pressure. How many do I need ...

Homework Statement https://dl.dropbox.com/u/63664351/Physics/MECH1.PNG Homework Equations Sum of Forces and Torque = 0 The Attempt at a Solution I found similar problem here: http://farside.ph.utexas.edu/teaching/301/lectures/node133.html Why is there no vertical reaction on a...

Hello, this is not really a homework question, but a question on a specific problem so I thought it belonged here rather than the General Physics subforum. This is a problem that was asked in our final exam, and I have doubts about it's "correct" solution. Here's a paint art to explain the...

Homework Statement Say there is a wall with width w meters and height h meters. There is a wind with velocity v m/s blowing on the wall at a 45 degree angle. The collisions of the air molecules with the wall are perfectly elastic. What is the magnitude of the force on the wall? (The density...

Should the driver apply brakes or turn the car in a circle of radius 'r' to avoid hitting the wall? This question is in the excercise of circular motion chapter. In this question I don't uderstand from where to start. Some help would be greatly appreciated.

Hello everyone! I was just reading about the working of Newton's Cradles and ended up having some confusion. When a ball is taken to a certain height and dropped, it comes down and hits the next ball. Now the explanation as to why the first ball stops and doesn't bounce back is attributed...

Homework Statement A system consists of two blocks each of mass M, connected by a spring of force constant k. The system is initially shoved against a wall so that the spring is compressed a distance D from its original uncompressed length. Floor is frictionless. The system is now released...

I have this dc heli called protocol. It charges from the remote which uses 6 aa batteries. So I got a 9 V wall wart. There's a couple problems with the wallwart when I used my analog multimeter to read the voltage it was reading 60 V. When I measured the batteries in the remote ball the remote...

Homework Statement A cavity block wall of area 10m2 constructed of 100 mm concrete, 50 mm air gap, 50 mm of polystyrene and a second 100 mm wall of concrete. The wall contains three windows with dimensions of 0.5 m x 0.7 m with glass 4 mm thick. The outside temperature is 5 °c and the inside...

Hey guys! I find it confusing to prove "mv^2/L", the average force acted by the air molecules on a wall in a box. My textbook tells me an assumption "the time during each molecules colliding with the wall of the container is negligible compared with the time elapsed between successive collision"...

Homework Statement Just took my finals and there was one problem that bugged me, I have done these types of problems multiple times and understand it well but this particular problem seems like there isn't enough information. There is a massless beam being held against a wall by a massless...

Homework Statement In an electrically heated home, the temperature of the ground in contact with a concrete basement wall is 13.8oC. The temperature at the inside surface of the wall is 20.8oC. The wall is 0.118m thick and has an area of 9.43m2. Assume one kilowatt*hour of electrical energy...

Hi all, Am currently studying a set of data from a Hot Wire Anemeotry lab that was done a few days ago. The experiment was investigating a turbulent flow of air in a wind tunnel near a flat wall. As part of the write up, we're ment to find the friction velocity from the laminar near wall...