Length Definition and 1000 Threads

Going through my physics assignment tonight, so that's 10 questions I'll be posting. Since I'm thoroughly hopeless at this subject most of my attempts will be based on my elite google-fu or trawling through lecture notes, bear with me and thanks! 1. Homework Statement frequency (f)=160hz...

If young modulus = stress/strain Wouldn't a different original length affect the value of young modulus ?

Homework Statement I can't understand the concept of internal path length. I can't understand what this value mean in the tree? For instance if a IPL of a tree is 30 then what does it mean for the tree. Tree does not have 30 nodes so what the path length means? Li is the number of nodes in...

Hello Forum, In the case of an ideal, thin lens (free from any aberration), it does not matter which face of the lens is facing the object. The results will be identical. What if the lens was an ideal (no aberration) thick less with the H planes, etc...? Would it matter which lens surface is...

Homework Statement A horizontally oriented string with mass per unit length ##\mu=0.1kgm^{-1}## is under tension T=1.0N. The left end of the string moves up and down in a simple harmonic motion with an amplitude A=0.10m and frequency f=3.0Hz. This sets up a sinusoidal wave along the string with...

Dear All, Apologies if this question isn’t really in the right place. I wanted to check I’ve understood some data correctly. The link below shows lunar cycles all the way back to 2000 BC: http://astropixels.com/ephemeris/phasescat/phasescat.html. Suppose I click on a table and get a date of...

When I first learned special relativity it was on an elementary level. I was told that "space itself" contracts in a moving reference frame. Now I am studying electrodynamics out of Griffiths. I just read the derivation of the Lienard-Wiechert potential and the fields for a moving charge...

Homework Statement A wave along a 15 gram string travels at 756 m/s when it is tightened to 189N? Homework Equations V = sqr root T/ m/l The Attempt at a Solution [/B] I got 3.30 x 10^-4

Homework Statement This is a silly question... but I know that a lens has two focal points but one focal length. If each focal point is at 5cm from the lens, would the focal length be 5cm, or 10cm (adding the position of each focal point together)? Homework Equations N/A The Attempt at a...

Homework Statement A wooden cube with the length of 10 cm is and a density of 700 kg/m^3 is floating on water A)Find the submerged parts length of the cube B) find the maximum added mass to the block before it becomes totally submerged Homework Equations FB=density*volume*gravity FB=Fg...

Homework Statement Hi! I have lately come across some tricky experimental physics tasks, where no solution is given. Some of them involved parts where the focal length of a convex lens had to be measured with a laser. How do you do this? Homework Equations 1/l + 1/d = 1/f (1) where f is the...

can you please explain me why don't we use arc length formula to calculate wavelength? seems a bit confusing...

There are characteristic lengths for Reynold's, Grashof, Nusselt, and Biot number but the method of obtaining them is not given in my notes. I would like to know how to do so for a plane wall, cylinder and sphere. Thank you.

If you know the focal length of a lens and use the lens equation 1/do + 1/di = 1/f by assigning some arbitrary do and solve for di, can you then find the magnification just from the focal length from -di/do?

Simple geometry can compute the height of an object from the object's shadow length and shadow angle using the formula: tan(angleElevation) = treeHeight / shadowLength. Given the shadow length and angle of elevation, compute the tree height. #include <iostream> #include <cmath> using namespace...

Moved from non-homework section, so the homework template is missing. Distance difference between A and B must be 0.25 or 0.75, find length of A and B in any possible value within radius of circle. Is there a name of theory to find this problem? here's my try. for A at any point on...

Hello everyone! The goal is to calculate the length of octanthiols in full stretched all-trans configuration. The structural formula is HS-C_7H_17-CH_3 witch is an alkyl chain terminated with sulfur. I used Avogadro software to build and model the structure. After i let it measure the distance...

Hi, In transmission coefficient T= exp(-2sqrt(2m(U-E)/hbar^2)L), L, as I interpret it, is the distance of the potential barrier. I am wondering if I have N particles all with kinetic energy E, approaching the barrier, can I integrate the transmission coefficient over a distance from infinity to...

Hello First of all, I was told this is a physics problem. If it's incorrect, I apologize. I have an image I want to know the length of the black ship (the ship which is carrying a ship). Let's assume that I know the length of the text on the ship (I have a reference object). Is this...

Homework Statement a solenoid inductor consists of 200 closely spaced turns, length = diameter = 5cm. calculate inductance. Homework EquationsThe Attempt at a Solution H = NI/L L = N (flux) / I - you can't use this because the length is equal to the diameter. What equation do I use?

Homework Statement If I found how much it stretches, do I just add it to the original length I started with to find total new length? For instance, the original length was 1.168m and I found x to be 0.90m, do I just add them together for the total length? Homework Equations F=kx The Attempt...

Homework Statement What would the focal length be of a diffraction grating if the set up is a laser placed 1 m from the 0 order diffraction? Would it be the distance from the grating to the laser or the distance from the grating to the image? Homework Equations 1/f = 1/o + 1/i Rd = [Df]-1...

I'm trying to write a simple script in blender python in order to show load deflection in cloth simulation. My question is: Is it possible to translate the change of length (distance between two nodes), into a force? (Newton between those nodes)? In addition you will find a minimal example. The...

I read this in Gordon's book "Structures or why things don't fall down". I read that the maximum length of lintel should be a maximum of 2.5 metres. Why? What if its more?

Tom Clancy's first novels were known for being fairly accurate from a technical/scientific point of view. That doesn't mean that they were 100% accurate, of course, but the author reportedly had some really good insider sources and knew what to ask them. I remember to have read the same thing...

I read that: "Length contraction is caused because moving objects bend space. And that is the difference between Lorentz's and Einstein's length contraction concepts. Lorentz thought length contraction really occurs but Einstein thought that length contraction is a consequence of bending space...

Maybe a stupid question and maybe sensless to ask, but as I don't know, I ask anyway: what is the length of the newly found gravitational waves in terms of traditional EM wavelengths?

I have a very basic question about the relativity of simultaneity (damn that's a mouth full). So basically rule no. 1 would be that it's all relative right? In the example of the ladder thought experiment it's shown that because of "Lorentz length contraction" a ladder which is bigger than a...

When there is Capillary rise in tube of insufficient length, why does not the liquid overflow?

(Sorry my bad English). I'd like to know if a body traveling near the speed of light really experiences a length contraction or if it SEEMS to be contracted for an observer in a inertial frame.

I know that an arc length in polar coordinates can be computed by integrating $$\int ds$$ using the formula ##ds=\sqrt{\rho^2 + \frac{dr}{d\theta}^2}d\theta##. But, seeing that ##s=\rho\theta## and ##ds = \rho d\theta##, why is it wrong to calculate arc lengths with this expression for ##ds##?

Homework Statement Letting c(t) =(t2,t,3) for 0<t<1 (Really it's a smaller than or equal to sign) 1. Find the length of the path 2. Find the average y coordinate along the path Homework Equations What we're given in the book: (These equations are not necessarily relevant) (formula 1) l(c)...

I was reading about (The train-and-platform thought experiment) from https://en.wikipedia.org/wiki/Relativity_of_simultaneity and was wondering a couple of things. 1.) Would the observer on the train agree with the stationary observer that event A and B happen at the same place in the stationary...

Hello, I have a question about the chord length of rotor blades from wind turbines. I do not really understand what the difference is to the radius of a wind turbine. I can not find a real explanation, but it seems to be very important. I know that the formula of the chord length depends on...

Homework Statement After year of over-eating and no exercise, Uncle Joe's is overweight, with a waist 50cm wide. He's also out of shape and can only hold his breath for 20 seconds. Worse, he can only jump 20cm high. But at his high-school reunion, he'd like to fool his old friends who haven;t...

Homework Statement transfer 650 EJ (10^18 joules) into an ice cube of unknown size. the temperature of h20 increases from -10c to 20c. Given: 1) q=mc(t2-t1) 2) for phase change q=m(F) specific heat of ice (c)= 2.22x10^3 J.kg^-1.K-1 heat of fusion (f)= 3.33x10^5 J/kg specific heat of water (c)...

Homework Statement A ripple tank is setup and a point selected on the second nodal line. determine the change in path length from two wave sources if they are in phase and separated by 2cm and the wave length is 5cm Homework Equations not really sure of what equations to use? The Attempt at a...

Lorentz contraction problem: By Bertrand Boucquillon Components of the problem: - Bob (observer) - 2 identical rods that both measure 1 meter. Let's call them rod X and rod Y - Point A - Point B Scenario (step by step): 1) Bob is at point A, and is at rest with both rods in his hands 2) Bob...

Homework Statement the equation of a stationary wave produced on a string whose both ends are fixed is given by y= [0.6sin(pi/10)x]cos(600pi)t what could be the smallest length of string?Homework Equations k=2pi/wavelength The Attempt at a Solution i got the wavelength to be 20 but don't know...

Homework Statement The resonant length of a closed air column at the first resonance is 0.375m, what is the wavelength when at 4th reasonance Homework EquationsThe Attempt at a Solution 1/4λ=0.375m λ=1.5m 1.5m/7 = 0.214m

Area_sector = 0.5 (radius)^2 * angle Arc length= radius * angle Can it be said and proven that the area of a sector is the integral of the arc length? What would that even mean?

Homework Statement You are watching a race between two space ships who pass you moving at different constant speeds. In your reference frame, both ships are the same length while moving. It takes the first ship 26.8 minutes to get to the finish line a distance 14 light-minutes away. It takes...

Consider the segment of the curve $y = \cosh(ax)/a$ between $x = −l$ and $l$. Here $a$ and $l$ are positive constants. Find an explicit expression for the length of this curve segment in terms of $a$ and $l$, as well as its limit for $a \to 0$. What I had done: Using the formula $\displaystyle...

Homework Statement Aluminium (Ar = 26.98, ρ = 2700 kg/m3) has cross-section of thermal neutron absorption 0.23 barn. What is the absorption length of thermal neutrons in the aluminium? What value decreases neutron intensity in 0.6 mm, 8 mm and 80 mm aluminium? Homework Equations Beer-Lambert...

Hi everyone, I read somewhere that when a coil is wound on a magnetic core it's electrical length becomes longer than it's physical length. I remember seeing this formula L=l * sqrt Ue Where L= Electrical length l=actual (physical) length Ue=Core permeability Does anyone know if this is...

Hey, I'm currently working on an explanation of the special Relativity. Now I'm at the point of explaining length contraction, but I don't understand why the following example is a reason for length contraction to exist: Imagine we have two Lightclocks in a fast moving Rocket. Lightclock 1...

In which book is it written that the only measurable physical quantity is the length? Task. In any book I've seen thoughts and images that very clearly illustrate the sequence of actions and implicit assumptions when measuring something. The result has been that in any measurement key was the...

I was looking at the barn door paradox, http://math.ucr.edu/home/baez/physics/Relativity/SR/barn_pole.html But supposing that instead of a barn, there was a piece of measuring apparatus which was in two halves, with a gap in between through which the pole would pass. One half of the measuring...

Could you use the formula "planck length/c=planck time" to convert time into a spatial distance? Using that to tell how far something is through time.

That's the image. I can't see how the edge of that middle triangle's length is Rθ at all. I've tried using similar triangles and law of cosines to figure that out but I'm missing lengths. I thought Rθ was the arc length of a piece of a circle? So if Rθ is a length of a piece of a circle, how is...