Deriving motion equations for two blocks on a rough table]]>

Two coaxial shafts are to be connected by a flanged coupling having six 15 mm diameter bolts equally spaced around a 300 mm diameter pitch circle. Determine the shear stress in the bolts when 300 kW is transmitted at 400...

Determine the shear stress in the bolts]]>

will either of them explode?

ok just kidding.

which one exerts more pressure, and is hence more likely to explode?

did heating the substance turn heat into force? (force per unit area)]]>

A person pulls three crates over a smooth horizontal floor at an angle of 34 degrees to the horizontal. The crates are connected to each other by identical horizontal strings A and B, each of which can support a maximum...

What is the largest pulling force before the string break?]]>

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[itex] \overrightarrow{F} = \frac{1}{4\pi\epsilon_0}\frac{qQ}{r^2}\hat{r} [/itex]

I found to hard summarizing all forces directly...

Calculation of the net force on a test charge]]>

Good coordinates and degree of freedom]]>

It was first stated that,

##\langle Q \rangle = \int \Psi ^* \hat{Q} \Psi dx = \langle \Psi | \hat{Q} \Psi \rangle##

and because expectation values are real,...

Hermitian Operators: Referencing Griffiths]]>

Find critical points and inflection points of:

1/[x(x-1)]

1/[x(x-1)]

using quotient rule, we obtain

(0-(2x-1)/(x^2-x)^2

set -2x+1=0 we get 1/2 for critical...

find inflection points of polynomials.]]>

I have a tennis racquet that has a certain weight distribution that makes it play very well. Due to quality control issues from the manufacturer my second racquet of same make and model has a very different weight profile, making matching difficult.

I'd like to determine the weight...

How to measure distribution of weight across solid object]]>

It gets some speed and then brakes, and the front goes down.Just when it stops, and the load tranfer is done, theres no force from...

Can a car ever sit like this?]]>

I finally now own an Arduino UNO with the starter kit and having completed all the projects in the book am looking for ways to extend myself with Arduino. I have had a look at many DIY websites (makesine, hackster.io,...

EE and DIY Websites -- Arduino]]>

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The goal here is to increase/decrease the angle x by 5 degrees. the black circles represent a rubber tire (same as car tires, only smaller), 5cm in diameter, rotating on it's center, powered by a motor. each wheel has 40 psi (2.76...

Linear movement vs rotation]]>

Open-Source uC Circuit Boards -- Comparisons & Conversation]]>

I built a generator for fun and I would like to find out how much power it is producing when I use it. I have a way of measuring mechanical power in but I am not quite sure on how to measure electrical power out. I'm thinking I could use some LEDs to create a load (or maybe...

Measuring the Power Output of a Generator]]>

It's difficult to discuss the science behind...

Merging neutron stars]]>

Consider a "dual" phased array antenna that has every odd-numbered radiating element driven from input port 1 and every...

Co-located pair of Phased Array Antennas]]>

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My notes state the Lemma as shown above. I believe one of the underlying conditions is that the arc we integrate over must be +ve oriented (anti-clockwise) in the Upper and Lower half of the...

Jordan's Lemma: Conditions]]>

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##dS = \frac{1}{T} (dU - PdV)## assuming dN = 0

I have actually managed to solve all 4 parts correctly, except for the fact that I...

Thermal Physics: Thermodynamic Identity]]>

I considered ##E## as a...

Trying to understand Dirac Hamiltonian]]>

https://imgur.com/a/aVCeU

(1/Req) = (1/Rv1) +(1/Rv2)

Req = Rv1 + Rv2

I'm not sure which formula is the correct one to use.

So..

I'm absolutely...

Equivalent Resistance of Figure]]>

I was wondering how tight the molecules that hold the cellular components are? Is it possible for a lipid in a cell membrane to sort-of-speak,"fly off" or kinda get "pushed out"? And then find itself absorbed into another cell wall or nowhere at all. And can that apply to any other...

Can a biomolecule from one cell's cellular component migrate]]>

It's the science class I wish I'd had before becoming an engineer at MIT.

In year 3, we are with Einstein and...

Teacher needs help: Bra–ket notation for parabolas?]]>

Solve the following coupled differential equations by finding the eigenvectors and eigenvalues of the matrix and using it to calculate the matrix exponent:

$$\frac{df}{dz}=i\delta f(z)+i\kappa b(z)$$

$$\frac{db}{dz}=-i\delta...

Coupled differential equations using matrix exponent]]>

Breakdown of Gauss' Law?]]>

The above link explains what brain waves are.

There are also visual/auditory equivalent to brain waves (also known as brainwave entrainment), explained below....

Audio Brainwaves?]]>

Imagine you have two RLC circuits you are trying to scan for resonances. They have identical resonant frequencies, but circuit 1 has a very high Q-factor

(Q1 >> 1), and circuit 2 has a very low Q-factor (Q2 < 1). Lets assume you...

RLC Circuits - Q Factor and Amplitude]]>

My Introduction]]>

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- Voc=kt/q x ln(tpXGlXNd/(ni)
^{2}) - Isc=A x q x Lp x Gl
- Lp=√(Dp×tp)
- FF=Pma/(Isc*Voc)

I got Voc=.298...

Solar Cell Problem(semiconductor)]]>

We are doing water rockets and I don't know how to calculate the height it went from it's hang time. It's total hang time was 7.35 seconds, and I know it's vertical acceleration was -9.8m/s^2 from gravity, and I'm assuming I...

Height From Hangtime]]>

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Suppose we have a rod of unit length placed stationary in frame S. According to an observer in frame S' (which is moving at a...

Can't understand this argument for Lorentz transformation y'=y]]>

Note that the masses are both at rest, and begin to push off of eachother in opposite directions.

Their velocity is measured when they reach 20cms distance. (I...

Average Force of two people pushing away on carts]]>

Is there something I missed on the news?

What is the alternative theory to dark matter and how does it explain 'things' ?]]>

1) We now know, FOR THE FIRST TIME, the rate of expansion of the universe (which they...

Time Magazine strikes again]]>

Nuclear batteries on space probes]]>

Telescope guiding techniques]]>

The human mind and belief]]>

Show that the (1,0,0) and (2,0,0) wave functions are properly normalized.

We know that:

Ψ(1,0,0) = (2/(a0^(3/2))*e^(-r/a0)*(1/sqrt(2))*(1/sqrt(2*pi))

where:

R(r) = (2/(a0^(3/2))*e^(-r/a0)

Θ(θ) = (1/sqrt(2))

Φ(φ) =...

Show that the Hydrogen wave functions are normalized?]]>

question about transfer function and amplitudes]]>

Negative pressure in house after winterizing]]>

My friend's son thinks his professor hates him]]>

So I'm doing an experiment at uni which I have to find out the specific heat capacity of given small solid cylinder. We are given an insulated canister(a dewar flask) standing on a scale where we have to pour Liquid...

Is the mass of Liquid N2 and its rate of mass loss related?]]>

If function ##f## is defined as such that ##f\left(x\right)=x^{\frac{1}{\sum_{n=1}^∞x^n}}##, then prove that the area enclosed between the the derivative function, ##f'(x)##, and the ##x##-axis is equal to ##1## sq unit

Prove the enclosed area of this function is equal to 1]]>

But given...

'Massless' Electrons in Graphene]]>

How much of pump power goes to heating the fluid?]]>

find maxima/minima of following equation.

-(x+1)(x-1)^2

(-x-1)(x-1)^2

Using product rule, we obtain,

-1(x-1)^2+(-x-1)*2(x-1)

I don't know where to go from here....

Find maxima/minima of polynomials]]>

When using Mathematica I input the code

Code (Text):

f1[a_, n_] :=

f1[a, n] =

Join[Table[LegendreP[k, x], {k, 0, n, 1}],

Table[LegendreP[k, x], {k, 1, n, 1}]]

Question about updating functions.]]>

My analysis...

There are two tuned circuit tuned to same frequency . In primary circuit at low frequency XL is low and large amount of current will flow at the inductor L1, now due to...

Discussing primary resistance of a double tuned ciruit]]>

I recently got into hard rock and similar genres, and became a big Led Zeppelin fan. Besides them, I listen to a lot of Pink Floyd, AC/DC, Styx, and Def Leppard.

All in all, though, LZ is my favorite band and my favorite song would have to be...

Favorite Bands]]>

explicitly either the radius vector r of the particle or the time t, i.e. L must be a function of v only

but the lagrangian definition is ##L=\int L(\dot q,q,t)##, so velocity appears in the...

Law of inertia]]>

I recently wrote a program in MATLAB to orthonormalize continuous functions on a given interval ##x\in[a,b]##. Lets call the initial linearly independent functions I seek to orthonormalize ##L_i## and let's call these functions ##\psi_i## after I orthonormalize them.

After running my...

Checking Gram-Schmidt]]>

Also a lot of...

This place is strange]]>

I used that TM=M x TpM. So, the question is:

Is tangent bundle TM the product manifold of M and T_pM?]]>

I became uncertain of my understanding of the physics after the plane starts to descend.

What I imagine happens is that your forward velocity would remain constant and you would...

What (if anything) limits the speed of something falling into a black hole?]]>

https://www.washingtonpost.com/news...n-continent/?tid=a_inl&utm_term=.4b5fe197fe45

EDIT: and here is the scientific report:...

New Zealand - The Tip of A Hidden Continent]]>

I apologize for joining your forum just to inquire about something that should be relatively simple, but you seem like a group of physics geeks able to articulate coherent arguments, and I need someone/s to help me see a different perspective on how to make an argument. For the...

Help a HS teacher understand uniform motion?]]>

Is a gold electrode supposed to corrode during electrolysis?]]>

Dreaming to be a scientist (physicist), can I do it?]]>

Is there a stellar type that would make Firefly possible?]]>

History of physics]]>

1. For an accretion disk, ## v_r<<c_s ## Why?

2. The conservation of mass equation is derived as,

The mass in an annulus of radius ##\Delta r## is ##2\pi r \Delta r\Sigma ## and it is...

Questions about Accretion disk]]>

At the onset of convection does this correspond to a Nusselt number of 1?]]>

Show that this is a valid representation of the Dirac Delta function, where ε is positive and real:

[tex] \delta(x) = \frac{1}{\pi}\lim_{ε \rightarrow 0}\frac{ε}{x^2+ε^2} [/tex]

Valid Representation of Dirac Delta function]]>

I am prepping myself for a quantum course next semester at the graduate level. I am currently reading through the Cohen-Tannoudji Quantum Mechanics textbook. I have reached a section on the density operator and am confused about the general concept of the operator.

My confusion stems...

Qualitative Explanation of Density Operator]]>

Here is the last page of part 5.

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

Quantum foam]]>

But the technique of NMR (nuclear magnetic resonance)...

Existence of RF Photons]]>

My question is: Is there a double slit-experiment done with all of the measuring equipment in place and all of the equipment activated but without a conscious observer? Proving there is no differentation pattern regardless of a concious observer.

Thanks in advance]]>

Automation: What kind of trouble will it be?]]>

Colors Observed in Photoelastic Media]]>

If ##C## is a connected space in some topological space ##X##, then the closure ##\overline{C}## is connected.

Suppose that ##\overline{C} = A \cup B## is...

Closure of Connected Space is Connected]]>

Heathkit Model CP 1060 Capacitive Discharge Ignition]]>

A cylinder of radius 20cm is mounted on a horizontal axle coincident with its axis and is free to rotate. A light chord is wound onto it and a 50g mass hung from it. After release the mass drops 1m in 12seconds. What is the moment of...

Moment of Inertia]]>

Three freight cars of equal mass are coupled together. The freight cars are travelling at 6.7m/s down a straight track when they collide with two more stationary identical cars. If all five cars are coupled together after the...

Momentum: Freight cars problem]]>

A follow-up...

Penning Trap questions -- capacity, manufacturers, leakiness...]]>

An astronomer has independent measurements of both the apparent and absolute magnitudes of Alpha Centauri B, and a measurement of the extinction towards the star. Derive an algebraic expression for the distance to the star and...

Astrophysics - Simple question]]>

How to choose the largest reward but to be shared equally among the people choosing it]]>

U is internal energy, but what is u? if its internal energy at a specific state, then why its multiplied by mass? does not makes sense to me...]]>

Accelerometer vibration]]>

Finding Young’s modulus by bending a beam]]>

Help with statics questions]]>

In my...

What's in an electronics hobbyist's toolbox?]]>

What I mean is, is there any process that doesn't need the nervous system's involvement and does its functionality independently and not related to it....

Un-involvement of the nervous system in the body?]]>

Potential flows and Helmholtz decomposition]]>

All mass is relativistic?]]>

De Rham Period]]>

Point kinetics equation with one-group delayed neutrons,

dn/dt= ((ρ-β)/∧)n+λC

dC/dt= (β/Λ)n - λC

When a reactor in steady-state operation, derivative terms would be zero. From second equation,

C/n= β/λΛ is found. For given β=0.0065, λ=0.08 and Λ=0.0001, the ratio of the steady state...

Delayed neutron fraction]]>

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I keep getting something over 0 for my Y_11. I'm not sure what I'm...

Calculating y-parameters (admittance matrix)]]>

Evaluate the integral:

$$\int_{-\infty}^{\infty} dx *\dfrac {\delta (x^2-2ax)} {x+b}$$

$$ x^2-2ax=0 $$

I know that the delta function can only be none zero when...

integrating a delta function of a function]]>