I hope to be starting some interesting threads here, resulting in, I hope, some fascinating discussions.]]>

Code (C):

#include<bcm2835.h>

#define LED RPI_GPIO_P1_12

int main(int argc, char **argv)

{

if(!bcm2835_init()) return 1;

bcm2835_gpio_fsel(LED, BCM2835_GPIO_FSEL_OUTP);

unsigned int delay(1000);...

#define LED RPI_GPIO_P1_12

int main(int argc, char **argv)

{

if(!bcm2835_init()) return 1;

bcm2835_gpio_fsel(LED, BCM2835_GPIO_FSEL_OUTP);

unsigned int delay(1000);...

how to solve the following equation?

I understand the mechanics of jumping straight up and landing on the same spot when inside of a moving bus travelling at a constant velocity but what happens when I jump straight up when skateboarding downhill? Do I land on the same spot on the skateboard, do I land further back relative to...

Jumping straight up while skateboarding downhill]]>

Given the ##\vec r(t) = ae^{kt}## , ##\vec θ(t)=kt## find the velocity function that is dependent on ##r##.

##\vec v(r)=?##

3. The attempt at a solution

My attempt:

1)##\vec r(t) = ae^{kt}##

2)##\vec...

Determining the velocity function]]>

New to the site and I'm liking what I've come across so far but I'm having some trouble with a project of mine. I'm an ME by trade but this is definitely more of an electrical engineering problem. I need to make a small turbine generator that operates in a water wheel type design...

Turbine Generator Coils]]>

Material - Timber - simply supported.

Cross section 240mm x 80mm

Allowable bending stress = 5N/mm2

Length - 4m

if...

Calculating maximum allowable load when given max stress.]]>

This is a followup to a question I asked a number of years ago about the Unruh effect. I understand that an accelerated observer will see warm gas of particles following a blackbody distribution with some temperature T, where as an inertial observer would see none.

My question is: how...

Unruh effect, temperature and particle density...]]>

just saying HI!!]]>

The principle states that a universal computing device can simulate every physical process.

Not sure where to post this, as it seems like a pertinent question in proving the simulated universe thesis right or wrong along with

Proving The Church-Turing-Deutsch Principle]]>

My...

Metric components]]>

all im interested is if Vout increases or decreases not by how much

increasing V...

detect increasing or decreasing pot output]]>

Is having a surname which...

Is having a surname beginning with “A” a big advantage? (journal article authors)]]>

I tried explaining that my astrophysics degree will...

Is this a good plan to pursue astrophysics?]]>

If we place two perpendicularly oriented linear polarizers at a double slit, there will be no interference pattern. In the wave picture, this is trivial: Two waves with perpendicular polarization cannot interfere.

In a quantum picture, I've often seen the interpretation that the sheer...

What destroys interference: Possibility or actual measurment?]]>

Then I read this -

https://www.physicsforums.com/insights/vacuum-fluctuation-myth/

and now I think...

What is the mechanism behind Hawking radiation?]]>

I would like to learn Linux, but I'm not sure how to install it. I searched YouTube, and it appears that there is something called VirtualBox where you can install Ubuntu, for example, on a virtual machine from inside the Windows OS. Is this a good idea, or it's better to install it as a...

Linux on VirtualBox or Standalone]]>

Magnitude-5.3 earthquake hits Japan's Fukushima

http://www.usatoday.com/story/news/world/2013/09/19/japan-fukushima-nuclear-plant/2835493/

how can i convert this analog signal(vd across sense pins) to a digital signal to detect...

detect current direction in water]]>

Major breakthroughs of medicine in the last 20 years?]]>

On the surface of a river at ##t=0## there is a boat 1 (point ##F_0##) at a distance ##r_0## from the point ##O## (the coordinate beginning) which is on the right side of the coast (picture uploaded below). A line ##OF_0## makes...

Solving for the trajectory in the polar coordinate system]]>

- I hear the intensity of the rain hitting the roof of the car

- there is a lightening flash

- for a couple of seconds the rain intensity eases up noticeably, then resumes

- then the thunder clap follows a little bit later

It...

Lightening discharge's effect on rain fall velocity?]]>

plz comment]]>

I was wondering if the effects of G-Forces can be displaced?? e.g if a body or object is placed in water (more like encapsulated in water) & is then subjected to tremendous acceleration very quickly, would there still be a G-Force effect on the object inside the water?]]>

By quantum observer means a thing or something that can perceive superpositions or behave like in quantum computer fashion. Just mention any experiment that can make you test a quantum...

Quantum Observer]]>

Why do we still see cosmic background radiation]]>

I am working on a pre-analysis plan and have to specify what I am going to do with outliers. I have two categorical variables (5 levels and 2 levels) and I will be performing a chi-square test for independence.

I thought of using a boxplot to detect outliers, but now I am not sure if...

Outliers categorical data?]]>

Issues

1. Serious amount of 60hz hum.

2. Channel two gain and volume...

How do I deal with a failed electronic project]]>

Amplitudes, Probabilities and EPR]]>

I have a problem

Basically, in theory -- a damaged 1220mm dia pipeline sub-sea (-8msw) with a 500mm hole in the 12oclock position 600mm. Pipeline resting on the seabed

The goal of the problem is to flush the pipeline of its contents in both directions.

The idea - have a containment...

Upthrust Reaction - Water Injection @ 5bar -8msw Subsea]]>

given a linear transformer rated for 50kVA, 11000V/120V

How do I find the maximum apparent power? The prompt is to maximum apparent power while keeping the Load RMS voltage between 114V and 126V.

Vsource has a peak voltage of...

How to maximum apparent power through a linear transformer?]]>

The Great Projecto is fired from a cannon at a velocity of 29.8 m/s at an angle of 50.4 degrees. He lands in a net which is 2.0 m above his starting elevation. What is his velocity when he hits the net?

Projectile Motion]]>

A non-conducting sphere of radius

The maximum manitude of an electric field of a sphere.]]>

Link: http://i.imgur.com/JSm3Tqt.png

##\omega=2\pi t##

Fourier: ## Y(f)=\int ^{\infty}_{-\infty}y(t)\mathrm{exp}(-j\omega t)dt##

Linearity...

Find Fourier transform and plot spectrum by hand & MATLAB]]>

I need help with the proof of Lemma 1.25 ...

Lemma 1.25 reads as follows:...

Multiplication Maps on Algebras ... Bresar, Lemma 1.25 ...]]>

The two rays shown below, a and b, have different wavelengths. They travel through the glass prism as shown; 1) is this possible? 2) If this is possible, which has the longer wavelength, ray a or ray b?

[see attached figure]...

Optics Question: Prisms]]>

Using a braided cable such as RG 174 as a audio signal wire with the braid...

An idea I have for better shielding???]]>

Imagine that each random sequence that comes out of the SPOT detectors is a coded message. When...

Simple proof of Bell's theorem]]>

A 250V shunt dc motor runs at 1000rpm while taking a current of 25 A. The motor has armature and field resistance as 0.2W and 250W respectively. Calculate

(a) The speed when the load current is 50A.

(b) Armature torque...

DC Shunt Motor]]>

So the experimental data seem to suggest that at resonance (V

(RLC in series) What is the R Voltage when at resonance?]]>

Does time dilation prevent event horizon formation?]]>

Code (Text):

#include <stdio.h>

#include <stdbool.h>

#define MAX_STRING 256

#define MAX_LINHA 1024

typedef struct{

int dia, mes, ano;

}Data;

int contar_linhas(char fname[]) {

FILE *f;

Data

int soma=0;...

page 5. Tensor Perturbations

"Tensor perturbations do not couple strongly to the thermal background and so gravitational waves are only generated by quantum fluctuations, as in standard supercooled inflation".

Why? Tensor perturbations...

Gravitational waves in warm inflation]]>

The problem is about calculating the error on the area of a rectangular field.

What is known is that the sides of the rectangle are 120 m and 180 m, and they have been measured with a 10 m measuring tape. The tape has a...

error propagation (tape shorter than measured length)]]>

Could you tell me the reason that if pole is close to the imaginary axis, (1) can be same as (2).]]>

Solve ##2sin3x.sinx=1##

I used the identity ##( cos (A+B)= cos A cos B- sin A sin B),

(cos(A-B) = cos A cos B+sinA sinB)→

-(cos 4x-cos2x)= 2sin...

solve trigonometry problem]]>

Role of accelerating voltage in Davisson Germer experiment]]>

The example is straight from my textbook. Since the iron is being oxidized, and it has a negative cell potential to begin with, wouldn't you flip the equation to make it the anode and in the end add it to the other cell potential?]]>

This is the problem: A person blows through a straw between two empty soda cans. Do...

Blowing between two objects -- Why is the pressure low?]]>

find the anti-derivative of x

i have 0 idea where to even start. this was a question on my quiz today]]>

Playing trombone to 'wildlife':

]]>

In the "perche i nostri discorsi" thread, selfAdjoint gave a concise sketch of the direction that Carlo Rovelli sees in loop gravity

View attachment 109930

2. Relevant equations

I = Imax cos^2 ((2pi/lambda)dsin(theta))

.81Imax = Imax cos^2 ((2pi/lambda)dsin(theta))

To shorten up my work I divided out the Imax

3. The attempt at a solution

Not sure...

Find spacing between slits in a double slit experiement]]>

White Deaths Exceed Births]]>

Physics and computability.]]>

"Space and Stuff"]]>

The Fundamental Delusion of Scientists?]]>

If you have 1.25 mol TiO2. Answer this question:

1- The mas of Cl2

(1.25 mol TiO2) ((2 mol Cl2)/(1 mol Tio)) = 3 mol Cl2

(3 mol Cl2)((35.453 g Cl2)/(1 mol Cl2)) = 106.359 g Cl2

2- The mas of C

(1.25 mol TiO2) ((1 mol C)/(1 mol Tio)) =...

TiO2 + C + 2Cl = TiCl4 + CO2]]>

Here is the last page of part 5.

https://www.physicsforums.com/threads/random-thoughts-part-5.851969/page-134]]>

Turns out that Zoobyshoe beat me in posting about this in another thread, so he will officially be known...

Weird News]]>

So, i am confused whether...

Twisting at shear center / centroid]]>

List two postulates of special relativity and then in your own words explain how these two statements are synthesized in Einstein's theory.

1. The laws of physics are the same in all inertial...

Explain how postulates synthesized into Special Relativity?]]>

Turning on a switch somewhere in the circuit, sphere of influences, i.e. motions of electrons in wire and generation of Poynting vector around the wire,...

Spreading of electric current -- start signals in a circuit]]>

Hello.

Imagine a closed box with reflecting walls. Inside you have two...

About interference, momentum and thrust...]]>

Calcium carbonate primarily occurs as two crystalline forms, calcite and aragonite. The value of∆!° for the transition

CaCO3(calcite) ⇌ CaCO3(aragonite)

is +1.04 kJ·mol-1 at 25°C. At that temperature the density for calcite is...

Equilibrium pressure of calcium carbonate]]>

A viscous liquid with density and viscosity ##\rho## and ##\mu## respectively is discharged onto the upper surface of a cylinder with radius ##a## at a volume flow rate ##Q##. This is a gravity-driven flow, and it forms a film...

Wave Problem]]>

View attachment 109921

P=I*(I*)*R/2

R1 = 12

R2 = 20

L = 0.0531H

C = 265.26*10^(-6)F

W = 2*pi*60

L -> jwL = 20j

C = 1/(jwc) = -j10

Mesh equations:

Mesh 1...

AC power - Simulation and hand calculated values different]]>

Let's have any non-zero complex number

Domain of single-valued logarithm of complex number z]]>

I need some further help with the statement and proof of Lemma 1.24 ...

Lemma 1.24 reads as follows:...

Multiplication Maps on Algebras ... Further questions ...]]>

Vector Calculus: What do these terms mean?]]>

Say a positive charge is at (x,y,z)=(0,0,0) at t<0 then (1,0,0) at t>0.

Electric field at (x,y,z)=(l,0,0) is (a,0,0) at t<l/c then (b,0,0) at t>l/c thus a<b.

With time delay of l/c, what propagates from (x,y,z)=(0,0,0) to (l,0,0) ?

I do not think it is electromagnetic wave because it is...

What propagates changes of Coulomb force?]]>

discontinuities in the time derivative of the magnetic field]]>

Book recommendation for Introductory Plasma Physics?]]>

The state of carbon in stars]]>

Show that the polynomial f(x)=x^5-3x^4+6x^3+18x^2-3 is NOT solvable by radicals

I'm pretty sure that to prove that this polynomial is not solvable I am too show...

Showing a polynomial is not solvable by radicals]]>

as B moves to over A, ( A is a fixed point ) C slides up its guide slot and is stopped by a non compressible object and no amount of force can shift it further up.

measurements in units.

At this point >> how do I...

Lever and fulcrum calculation]]>

View attachment 108770

Hello everyone, I am trying to figure out how to approach part c, parts i and ii

OK. I know that we have the current equation in milliamps as shown above

Figuring out why experimental results are different]]>

Consider the beam shown in (Figure 1) . Suppose that a = 15 in. , b = 8 in. , c = 1 in., and d = 4 in.

Determine the moment of inertia for the beam's cross-sectional area about the x axis....

Parallel Axis Theorem- Composite Areas (STATICS)]]>

A golfer strikes a golf ball at an angle of 17 degrees above the horizontal. With what velocity must the ball be hit to reach the green which is a horizontal distance of 250 m from the golfer? It is at the same height as the...

Projectile Motion: golf ball velocity to reach the green]]>

I know that construction lines were used when drafting was done by hand. Now, we do everything on the computer. So, how are they used on the computer?

Also, how are guidelines used in autodesk? Were they not used in manual drafting also? How are they used in computer drafting?...

How are construction lines used in autodesk?]]>

Got another one?]]>

Real Research in Unexpected Places - Backyards, Barns, Bayous...

Real Research in Unexpected Places - Backyards, Barns, Bayous - Comments]]>

Im having some issues with my task.

1. The problem statement, all variables and given/known data

The heat generation rate of a cylindrical fuel (D=0.2 m and 1 m long) is 160 kW.

The thermal conductivity of the fuel is 100 W/mK and its surface temperature is

maintained at 283 K....

One-dimensional steady state conduction in Cylindrical coordinates]]>

Radar (radio wave) is placed 35m above sea level. Calculate working range of radar.

So I have found various different formulas for range but they all are very complicated with respect to my...

Radar and simple range problem]]>

Top Graduate Schools for Quantum Information and Computing]]>

A regulation volleyball court is L = 18.0 m long and a regulation volleyball net is

Volleyball problem]]>

A small block of mass 1.74 kg rests on the left edge of a block of length 3.05 m and mass 7.95 kg. The coeﬃcient of kinetic friction between the two blocks is 0.279, and the surface on which the 7.95 kg block rests is...

Kinetic Friction problem]]>

Noise induced in a wire]]>

R = 1 kohm and Vs(t) is sinusoidal of (peak) amplitude 3 V. The diode is modelled by the series combination of an ideal diode and 0.7 V voltage source.

For what percentage of time will the diode conduct?

answer: 42.5...

Diode Circuit]]>