Constant Definition and 1000 Threads

Homework Statement Hello, In a lab experiment, we wanted to compare the time constant in a simple RC circuit by comparing the value of Resistance * Capacitance that we measure directly and the value of RC that we get from the procedure. The procedure entailed using a wave generator and an...

Hi all, I have a constant torque spring that rotates the drive wheel of a Geneva mechanism. I am facing the following problem. I would like a very slow rotation of the drive wheel whenever the drive wheel is not driving the Geneva wheel of the Geneva mechanism (which is 270 degrees of a...

Homework Statement Warning: I realize the title is misleading... the function itself isn't what's constant. Mod note: Edited to fix the LaTeX If ##f## is a continuous at 0 such that ##\lim_{x \to 0}\frac{f(x)-f(g(x))}{g(x)}=M##, where ##g(x)\to 0## as ##x\to 0## does this generally mean that...

I searched for, but could not find any name or published value for a constant (with units m-3 K-3) which when multiplied by temperature (in degrees Kelvin) cubed gave the corresponding photon density (in m-3). Does anyone know of such a constant with a published value? I calculated a value, but...

Hello, I've noticed that Planck's constant h and the action of a particle S both share the units of Joule-second. I was wondering if there were a connection between the two, but my Modern Physics textbook (Harris) doesn't say anything about it. Wikipedia's definition of Planck's constant says...

Homework Statement Prove that if f'(x) = g'(x) for all x in an interval (a,b) then f-g is constant on (a,b) then f-g is constant on (a,b) that is f(x) = g(x) + C Homework Equations Let C be a constant Let D be a constant The Attempt at a Solution f(x) = antiderivative(f'(x)) = f(x) + C g(x)=...

1. The problem: Building a (probably very simple) computational model for Ising Spins - particles on a lattice with spin up and spin down, only nearest neighbour interactions. I can't for the life of me figure out the renormalisation constant for the probability of a given particle flipping...

Homework Statement Show that phi_n will find the proper phi_4. IE: show that it gives the correct normalization constant. Richard Liboff...chapter 7 Homework Equations A_n = (2^n * n! * pi^1/2)^-1/2 The Attempt at a Solution I don't know where to start really. I tried some things with <...

When doing constant volume calorimetry, the enthalpy can be calculated as follows: ΔH = ΔU + Δ(PV) ΔH = w + q + Δ(PV) ΔH = PΔV + q + Δ(PV) and at constant volume: ΔH = q + VΔP which I've then see people rewrite using the ideal gas law as follows: ΔH = q + (Δn)RT where Δn is the change in...

Homework Statement A 15.0-N object is oscillating in simple harmonic motion at the end of an ideal vertical spring. Its vertical position y as a function of time t is given by y(t)=4.50 cos[(19.5s−1)t−π/8] in centimeters. What is the spring constant of the spring? Homework Equations y...

Homework Statement Solve the following differential equation and compare computer solutions \begin{equation*} 4y''+12y'+9=0 \end{equation*} Homework Equations None The Attempt at a Solution [/B] First of all looking at this equation, even though it is in the section where we learned about...

Fermi-Dirac distribution function is given by f(E)=(1)/(Aexp{E/k_{B}T}+1) here A is the normalization constant? How we can get A? E is the energy, k_{B} is the Boltzmann constant and T is the temperature. thank you

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...

Hello! The total force F = m*a applied to the bicycle is F = F1 - a*v^2, where F1 is the initial force applied to the bicycle, a is a constant and v is the velocity. That means that the total force applied to the bicycle decrease as velocity increases, like a wind resistance decreases...

Homework Statement It requires 49 J of work to stretch an ideal very light spring from a length of 1.4 m to a length of 2.9 m. What is the value of the spring constant of this spring? Homework Equations u=0.5kΔx2 The Attempt at a Solution u=\frac{1}{2}k\Delta x^2\\ k=\frac{2u}{\Delta x^2}\\...

A question on my lab is find the amount of "stopping force" required to stop the egg, by determining the size of the "crumple zone" A brief description of the lab: Build a container that will keep an egg from breaking as it is dropped from the third floor of the school, your container must...

what speed would you half to obtain going around the Earth to be constantly in line with sun, so it would be day time aways. and how would you go about calculating this. what kinds of equation could you use. Thanks Aiop.

Homework Statement Two cyclists, Anant and Beth, are standing on a straight road a distance d=22.0 m apart. Simultaneously, they begin to move toward each other, Anant with acceleration a_A=0.2 m/s^2 and Beth with acceleration a_b=0.10 m/s^2. Just as they begin to move, a bee, sitting on...

1. The problem statement, all variables and given/known Spring constant of trampoline and cradle Homework Equations k=F/x The Attempt at a Solution I think a trampoline should have a low spring constant so that the extension is bigger. Is this correct? For cradle, in my opinion, it should have...

I was going through Periodic Motion chapter of my book and came across an equation while defining the relation between Time Period of on oscillating particle and force constant. k/m=w2 which was applied in, T = 2xpie/angular velocity can anyone please help me define this equation. I can't seem...

Third question about wave optics in two days, hope it's not too much. When we look at the intensity of light on the screen in a double-slit interference experiment (assuming negligible diffraction), we find something like this : When we look at the intensity of light on screen in a...

Why do people say that RVs that have the normal distribution has a constant variance. What does that mean constant variance.

Hi I want to create a thought experiment involving waves of any kind. I am going to create a thought experiment I am on a boat that is at rest in the ocean. I am standing on the boat measuring the size of the waves and the frequency. So I measure the wave along the side of my boat to have a...

Homework Statement Show that the internal energy at constant entropy and volume decrease for a spontaneous process Homework Equations F = U-TS The Attempt at a Solution Use Clausius: dS-dQ/dT > 0 Assume constant volume: TdS > dU assume constant entropy this becomes 0>dU Since dU is...

Homework Statement We have a heavy chain with length of L and weight of m placed on a table. we take an end of it and move it with constant velocity of v upwards. so each moment it gets heavier. If the force needed for this uniform speed is called F, and length of chain which is higher than the...

I am an electrical guy, i can't understand the concept of constant flow system...and how temperature is controlled in room by Air conditioner...thanks

Acceleration due to gravity is used as a constant throughout the massive body,but it varies due to height and depth & also varies from equator to pole,so it affect the rotational speed of planet from equator to pole.So, why would it takes as a constant.

1. The problem statement, all variables and given/known Homework Equations P=Fv K.E = 1/2 mv2 The Attempt at a Solution This is the examiner report: Why infinite acceleration? Is it because the mass is too small?

Hi all, A question about the vacuum energy density and spectrum. The only spectrum that is frame invariant involves the cube of the frequency. Is it also possible to have a constant offset term (which would also be frame invariant), to 'adjust' the energy density so it doesn't turn out to be...

Homework Statement It is said that the potential in the neutral regions of a PN junction diode is CONSTANT. Homework Equations V=Q/4ΠΣr The Attempt at a Solution It is said in all textbooks to ASSUME that the electric field in the neutral regions as zero. Two aspects confuse me. 1. What...

Homework Statement The mass of a car that acts on one wheel is 100 kg. The elasticity (spring) constant in the suspension system of that wheel is k = 10^4N/m. Design the strut (find the friction/resistance constant c) such that any vertical motion of the wheel (set up for example by going over...

In the EFE, what does adding Λgμν mean and why is it not included in the Einstein tensor?

Assuming that we have a chemical plant which produces methanol through the following equations: CH4 + H2O <--> CO + 3H2 CO + 2H2 <--> CH3OH CO2 + 3H2 <--> CH3OH + H2O I know that with specific pressure, temperature and flow rates, I can produce reactions with specific equilibrium constants. Are...

Okay, so please help settle a dispute. A toy car is moving at a constant speed of 1 m/s. The car is powered by a battery. Now, when the car is going at a constant speed, there is obviously no net force on the car. The dispute comes when trying to draw a FBD. Is there friction (traction)...

Example 3 shows the derivation of one of the kinematics equations. I am quite familiar with it. At the part where it says dx/dt = gt + constant, how does one determine if constant = x_0 or v_0? Thank you.

When the textbook differentiated with respect to time, I see that the middle term is R(dI/dt). Why can't it be I(dR/dt)? When I differentiate, how do I know which letter to differentiate? 3. The Attempt at a Solution 2. Homework Equations 1. Homework Statement

Homework Statement A mass is attached to a spring which is mounted onto a wall. This mass is on a frictionless horizontal surface. You apply a CONSTANT force to the mass and it comes to a stop in 10 cm. My question is, that since the mass comes to a stop in 10 cm then: Force Applied = kx...

Hello everyone, How does Einstein established the equivalence between mass and energy, or in other words what is the fact that proves this.And why the constant is not just C but C square. Why C anyway ??

Homework Statement I'm given a initial and final pressure and temperature of an ideal gas to solve for the work done after it expans in a polytropic process (n=1.2) Homework Equations W = integral of P*dV PV = nRT PV = RT* PV = mRT PV^n = Constant The Attempt at a Solution I get W = integral...

1. Homework Statement A gas (treated as air) powered turbine provides power to a compressor which then sends the compressed air through an intercooler (heat exchanger). Turbine: Gas enters @ 0.03kg/s, 370 degrees Celsius Gas leaves @ 300 degrees Celsius and a "lower pressure" Compressor...

How to find value of integration constant?I know with the help of boundary conditions,but How boundary conditions help in finding integration constant?

Homework Statement Which one of these motions is at constant acceleration? A) A car moving at a constant speed and constant direction. B) A train making stops along its route. C) A moon orbiting a planet. Homework EquationsThe Attempt at a Solution I believe that A is an acceptable answer...

Hy friends I am new here and its my first post. Iwant to ask that a sattalite orbits around Earth with constant velocity.then it has acceleration or not?

Homework Statement In the Principles of Physics book chapter two in checkpoint 2 claims that If velocity of object is zero its a constant velocity.I am confused cause v=0 means there's no motion.Without motion we can't talk about constant velocity.I am confused.(The equation of object is...

In a simple series RC circuit, when t=RC, the voltage across the resistor and capacitor is the same. Why is this physically significant and why do we choose this as the time constant that dictates the cutoff frequency?

1. The scenario If we have a small cuboid volume embedded in a larger dito with periodic boundary conditions, and a wave function that is constant inside the former, while zero everywhere else; what can we then know about the momentum? Homework Equations I. Âψ = Aψ (A being the measured...

Hi, not a homework problem as such, but I am studying introductory quantum physics and having some trouble understanding how applying the rising or lowering operator for angular momentum implies: L+/-|l,m> ∝ |l, m+/-1> Basically, my question is the same as the first part (Q1) as described in...

Hello, Is the speed of light constant at all speeds? So will the speed of light (3 x 10^8 m/s) be the same if a person was traveling at 1000 km/hr and if they were stationary. Thanks

Homework Statement Under what conditions is \left\langle{{\mathbf{x} \cdot \mathbf{p}}}\right\rangle a constant. A proof of the quantum virial theorem starts with the computation of the commutator of \left[{\mathbf{x} \cdot \mathbf{p}},{H}\right] . Using that one can show for Heisenberg...

Homework Statement At what rate would stars have to be producing light (how many photons per second per solar mass start) in order for the energy density of photons in the universe be constant? Assume current values of cosmological parameters. Do it for current time. Homework Equations e =...