Constant Definition and 1000 Threads

Homework Statement I am trying to use a slide wire potentiometer and a galvanometer to find the electromotive force of an unknown cell. I have heard that the balance point at which the galvanometer needle has zero deflection should be towards the centre of the slide wire as this reduces...

Homework Statement Prove that the diffusion constant D of an ideal gas can be expressed as D=1/3λv(v bar) where λ is the mean free pass of the gas molecule. And v bar is the average speed of the gas molecules obtained from the kinetic theory of gases.(Use the picture to setup the net flux...

Homework Statement (Working with geometrised units) Consider the EFE ##G^{\alpha \beta }+\Lambda g^{\alpha \beta} = 8 \pi T^{\alpha \beta} ## work out (using weak-field considerations) an upper bound for the cosmological constant knowing that the radius of Pluto's orbit is 5.9 x 10^12 m...

Homework Statement You are asked to design spring bumpers for the walls of a parking garage. A freely rolling 1100 kg car moving at 0.66 m/s is to compress the spring no more than 9.0×10−2m before stopping. What should be the force constant of the spring? Assume that the spring has negligible...

In an electromagnetic wave like light,both wavelength and frequency changes but it's speed always remains constant.Why?

It states "a pure chemical compound is always made up of the same elements combined together in the same fixed ratio by mass." But how can a compound have the same elements ? For example,let's take ethanol,it is composed of hydrogen,carbon and oxygen.So three elements and not the same element.

I have an object that is decently thermally insulated. I want to plot how a constant cooling power of a few watts for a few minutes is going to affect the object's temperature. I need to account for how much heat is leaking in. Getting a constant cooling doesn't seem easy. If I instead use...

Homework Statement Given the following wave function valid over -a \le x \le a and which is 0 elsewhere, \psi(x) = 1/\sqrt{2a} Find the uncertainty in \left<\left(\Delta p\right)^2\right> momentum, and the uncertainty product \left<\left(\Delta x\right)^2\right>\left<\left(\Delta...

Consider a stable circular orbit (with a central force) subjected to small perturbations. The orbit equation is given by (3.45). The text argues that the ##\beta## in (3.46) must be a constant over the domain of ##r_0##: "Otherwise, since ##\beta## can take on only discrete rational values (for...

The triplet spin state with a normalisation constant of 1/√2 and the singlet spin state with the same normalisation constant... Where on Earth is this normalisation constant derived from? I've been scouring the Griffiths intro to quantum mechanics textbook and can't find info on it.

Many have claimed that if dark energy was not so small then the universe would fly apart and we wouldn't be here. However what if you increased the value of lambda and at the same increased the value of the gravitational constant ( or perhaps the amount of matter or dark matter in the universe)...

Homework Statement my spring constant is 85 N/cm and I have to convert to N/m Homework Equations why does stoichiometry not work on this? How would I approach conversions like this? The Attempt at a Solution I tried converting the 85 N/cm to N/m and ended up getting 85*10^2 N/m. This was...

Hi, Could I please get some guidance on my approach and solution, for this particular problem. Any assistance welcome. 1. Homework Statement An ideal gas is compressed at a constant pressure of 1.3 atm from a volume of 20 L to 12 L. During this process it gives off 3.69 kJ of heat. What is...

In my springs what would the spring constant need to be If I am 1.8m tall and I weigh 68 kg

When we measure the cosmological constant Λ what we are really doing is measuring the longterm value of the Hubble rate, namely H∞, the distance expansion rate that the present rate H(t) is seen to be declining towards and leveling out at. It's convenient to write distance expansion rates as...

When does the value of the "Equilibrium Constant (K)" equal one ? and what does that mean ?

In my textbook it says an isothermal process occurs when the temperature is constant. It also said taht typically, Q,W, and delta U are not 0 in these processes. My question is how can heat not be 0 if temperature is constant? Q=mcDeltaT so if Delta T is 0, then Q also has to be 0 right?

Homework Statement I need to explain for a lab, why the efficiency of a rubber band slingshot constant for different stretch lengths. I don't need math, just a general explanation of why kinetic energy of projectile/elastic potential energy in rubber band is constant. Homework EquationsThe...

Homework Statement A block of mass 1 kg is attached to a spring. The spring extends by 10 cm. Find spring constant.Homework EquationsThe Attempt at a Solution Potential energy of spring = kx2/2 work done by block = PE Hence mg*x=kx2/2 ∴1*9.8*0.1=k*0.1*0.1/2 ∴k=196N/m But solution says mg = kx...

Piran et al., "Cosmic explosions, life in the Universe and the Cosmological Constant," http://arxiv.org/abs/1508.01034 I thought this was interesting. If I'm understanding correctly, the idea is that satellite galaxies such as the Magellanic Clouds have low metallicity, which causes them to...

Homework Statement Choose two masses and vary their separation, measuring the force between them each time. Plot a straight line graph and use the gradient to estimate the universal gravitational constant. Include uncertainties in the results and express values with the appropriate number of...

Homework Statement Not sure if this belongs in the 'Advanced' section so apologies if it does not. I am using a monochromator to measure spectrum lines from a rubidium lamp. From the data (wavelength of spectral lines plus transition number 'n') I am asked to use a graphical method to...

Homework Statement A parallel plate capacitor has a capacitance of 1.5µF with air between the plates. The capacitor is connected a 12V battery and charged. The battery is then removed. When a dielectric is placed between the plates, a potential difference of 5.0V is measured across the plates...

Homework Statement A parallel plate capacitor has a capacitance of 1.5µF with air between the plates. The capacitor is connected a 12V battery and charged. The battery is then removed. When a dielectric is placed between the plates, a potential difference of 5.0V is measured across the plates...

Homework Statement A sample consisting of one mole of a diatomic perfect gas is heated from 25 °C to 200 °C at constant volume. Calculate q, w, ΔU and ΔH for the process, given that Cv = 23.02 J K-1 mol-1 . Homework Equations Im studying for mid terms and i have no lecture notes on diatomic...

Big masses like planets and stars have gravitational fields. Gravitational fields curve space around them. So in theory a particle having mass moving at fixed speed, from its own perspective, will accelerate when moving closer to such a planet. It'll be moving at fixed speed in a curved space...

Generally in chemistry and physics, we learned that a material has a heat capacity at constant pressure. However, I am confused at whether this refers to a constant external pressure or a constant system internal pressure? Thanks.

For time independent Schrodinger's equation in 3-D Where Enx,ny,nz=(nx/Lx2+ny/Ly2+nz/Lz2)(π2ħ2/2m and Ψnx,ny,nz=Asin(nxπx/Lx)sin(nyπy/Ly)sin(nzπz/Lz) How do I normalize A to get (2/L)^3/2? I don't think I understand how to normalize constants.

Homework Statement A ball of mass m rolls down a 3.0 m ramp inclined at 30° above the horizontal, rolls along a flat, friction less surface, and collides elastically with another ball of mass 2m, initially at rest. The second mass then moves along the surface and collides with a horizontally...

Excuse me, If I want to calculate one equation in SI units. Which value of Boltzmann constant I should deal with. Also, the electron temperature it can be used in Kev or it should be in ev. Also, the nm must be converted to meter or it can be used in nanometer.

Could anyone please recommend a paper that accurately gives the value of the cosmological constant? Or else may you reply with values of the cosmological constant that you would you use in your research? Any help would be very much appreciated.

Ok, so here's the deal. I'm working on something that I SHOULD know the equations for after 5 years of school and a degree in mechanical engineering, but then again I can't remember why I walked into a room most times. So if ya'll could give me some guidance and at least a starting point I...

Is the amount of dark energy in the universe constant or else does it increase as the universe expands? In other words is the "anti- gravitational force" that is believed to be caused by dark energy and results in a accelerating universal expansion, a constant value or will it increase as the...

I am reading an article on Arxiv about modelling the electron structure in a nanowire crystal: http://arxiv.org/abs/1511.08044 But I am having trouble understanding the hamiltonians (1) and (2). In (1) what is the purpose of the term E_gap/2. Is that just a reference point for the energy or...

Homework Statement A Ti Rod is to be put into a furnace to try and increase the carbon content of the rod. Initially, the carbon content of the rod is 0.2%wt. The carbon content of the furnace is 1.0%wt. What would the temperature have to be in order to get a final carbon content in the Ti rod...

So I have a diff eq dy/dx = ky - w where K and W are constant's I want to draw a phase portrait so i set ky - w = 0 and determine the expression equals 0 at y = w/k so I want to study the behavior of the solution greater w/k and less than w/k so I plug (2w/k) and (-2w/k) and check the...

I know the phase constant depends upon the choice of the instant t=0. Is it compulsory that the phase constant must be between [0,2π] ? I know that after 2π the motion will repeat itself so it will not really matter, but what is the conventional way to write the phase constant in the general...

In an experiment I hope to carry out, one of my "constants" are velocity (constant velocity). I must say a way I will keep this value constant. For example I can not say "I will try my best to pull mass at a constant velocity" "I will take a video of the experiment. When I examine the video, I...

Homework Statement The speed v of sound in a gas depends on the density p and pressure P of the gass. If this dependence is in the form of a power law that is, v = kpaPb where k, a and b are constants (k a dimensionless one). a. Determine by dimensional analysis the values of a and b. b...

One condition for wave interference is that the sources of the waves must be coherent, which means they emit identical waves with a constant phase difference. I can understand that identical waves means they have the same wavelength. However, I don't understand what is a constant phase...

Homework Statement Why for a given constant force, in a study reference system, which point of application moves from A to B, the work of the force is conservative? Homework EquationsThe Attempt at a Solution The only thing I know is that if the angle ##(\vec{F},\vec{AB})## is acute...

Homework Statement A car with a mass of 1,500 kg sits on a suspension system that has four springs. When the mass of the car was originally placed on the springs, they compressed by 10 cm. What is the spring constant for each spring? Homework Equations k = F/x or k = mg/x The Attempt at a...

Homework Statement Consider the nonlinear (ordinary) differential equation u' = u(1-u). a) Show that u_1 (x) = e^x/(1+e^x) and u_2(x) = 1 are solutions. b) Show that u_1+u_2 is not a solution. c) For which values of c is cu_1 a solution? How about cu_2 ? Homework Equations N/a The Attempt at...

I'm starting to question my sanity. This wikipedia article claims a ship with a constant acceleration of 1g will cross 100000 light-years in 24 years by traveller's clock: https://en.wikipedia.org/wiki/Space_travel_using_constant_acceleration Numerous calculators over the web give you the same...

How come that, in the context of discussing the search for gravitational waves, I never see the cosmological constant mentioned ? We know that ##\Lambda \neq 0##, so this seems strange to me; in the presence of a non-vanishing constant, the background is not Ricci flat in the vacuum case, so...

Since Edwin Hubble proposed distant galaxies move apart from each other as spectra of each galaxy is shifted towards the red end. this created the law that universe is expanding exponentially since big bang. and these galaxies spectra are due to stretching of wavelength of light incident from...

I realize that this is probably really basic, but I can't quite conceptualize a hollow metal sphere having constant voltage and zero electric field inside of it. I've searched around on the Internet, and I've seen stuff about Gauss' Law, but even after reading into that a little bit I can't make...

How does one arrive at the following equation to approximate spring constant for solids... using Hooke's Law F ∝-x ⇒ F = -kx and strain∝stress ? k = (m/a2) × (K/ρ)½ where k≡spring constant m ≡ mass of a single atom a ≡ atomic spacing K ≡ bulk modulus ρ ≡ density

Im trying to solve for a constant in an equation and it involves taking the arctanh(6.55) and my calculator is giving me an error, is there a way around this?

Homework Statement It's been a little while since I did one of these. My question is: We have to use http://phet.colorado.edu/sims/mass-spring-lab/mass-spring-lab_en.html to find the measurement of k, the spring factor using two different methods. For the method I am looking at, is the static...