Define f(x,y) = x+2y, w = x+y. What is ∂f / ∂w?

f = w+y so:

∂f/∂w = ∂(w+y)/∂w = ∂w/∂w + ∂y/∂w = 1 + ∂y/∂w. But I'm really not sure if this is right and if it...

Partial Derivative Problem]]>

Three identical particles, each possessing mass m and charge +q, are placed at the corners of an equilateral triangle with side r. The particles are simultaneously set free and start flying apart symmetrically due to coulomb's...

Work done by electric force]]>

Starting with Dark matter, to date the maths works out fine, but in the real world...

I am having a crisis in faith]]>

Rate of emission]]>

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I know for circular motion. The radial acceleration is always...

Linear Acceleration]]>

H. Nikolic

(Submitted on 2 Jul 2015)

We propose a new...

AdS/CFT w/out Holography and SLOT - Fluctuation Work Theorem]]>

Why do Physicists get paid so poorly?]]>

Maximum design load not to be exceeded, not including trailer weight which has not...

Capstan winch practical for long 2,000' towing up 1,000'?]]>

Collapse with and without measurement]]>

power of transformer]]>

Say we are observing plane wave patterns on table. The depth of water is the same everywhere in ripple tank. The frequency of waves is 12 Hz and wave length is L (lamda). We see the wave pattern as stationer while looking at...

Ripple tank - strobe frequency]]>

I put up the image so that you can see the hints if you're curious. I am supposed to prove that if ##...

Prove Sum Approximation Theorem]]>

"First Order" infinitesimals are finite variables prepended with the letter ##d##.

Infinitesimal of any order, are prepended with ##d^n## where ##n## is the infinitesimal "order".

Finite...

Can one define higher order infinitesimals?]]>

Hanging on to our them on the sun from last week, this week's contest is about two of my favorite time of the day: sunrise and sunset.

Your photo must be taken during one of those times of the day. It must clearly show or indicate that it was...

PF Photo Contest - Sunrise, Sunset (5/9-5/15)]]>

I have come up with the below stack which lists the...

Physics Stack]]>

An object of rotational inertia I is initially at rest. A torque is then applied to the object, causing it to begin rotating. The torque is applied for only one-quarter of a revolution, during which time its magnitude is given...

Rotational Motion]]>

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

This is the known data:

A isothermal process in the ascending conduit (like a chimney) of a closed-loop circuit, which is thermally insulated from the atmosphere,...

Work needed to expand a very heavy gas under high pressure]]>

Worked for many years in the energy industry; first as an electro-mechanical fitter, then as an engineer. Recently returned to study.

Here for advice and help!

cheers

W]]>

The dislocation can line at different angles. I can rotate the dislocation for any angle; but in relaity the angle is limited by the structure of the crystal: theta is...

How can I translate (move) a stress field a given distance?]]>

So here is...

Science fiction story]]>

MIT Physics Degree Requirements]]>

I get it - the faster the object is moving away from me, the more the light it emits moves to the red side of the spectrum.

But here's my question:

Here on earth, we watch galaxy A, which seems to have a very red light. How can we know it's not "originally" that red, and if it...

A basic question about redshifting]]>

Determine the field lines of the vector field ##\vec F = (x^2+y^2)^{-1} (-y\hat x + x\hat y)##

Definition of a field line

##\frac{d\vec r (\tau ) }{d\tau } = C \vec F (\vec r (\tau )) ##

Constructing field lines]]>

stopping potential]]>

This week, we will try something a bit different, and there will be a greater involvement of the voting members.

Your task this week is to take a photo of an ordinary object, but in such a way that it is unusual and unrecognizable. You may, for...

PF Photo Contest - What Is It? (7/4-7/10)]]>

MY question is that should I do my bachelor's in Mech or Elec Engineering for later doing Master's in mechatronics and yet having my options open for Energy Engineering, Aerospace Engineering and...

What is the best approach for MS/ME mechatronics?]]>

Best Songs Ever 2]]>

=> F.S = 1/2*m*(v

=>(ma).s = 1/2*m*(v

Tangential and Centripetal Acceleration in Circular Motion]]>

Dave]]>

find series expansion of relativistic energy formula, At what speed is there a 10% correlation to the non relativistic KE.

$$ E=\frac{mc^2}{\sqrt(1- \frac{v^2}{c^2})} = mc^2 + \frac{1}{2}mv^2 + ......

Correction to non relativistic KE]]>

So far, for months, it was just usual bickering and last moment deals. It seems that this time is...

Greece closes banks and imposes capital control]]>