Recent content by MasterX

Hi, I am just thinking out loud, but I believe that I am on the right track. As the plate rotates around the thread, three different forces are exerted on it: 1) Force from the string 2) Gravity 3) Centrifugal force The second force will force some parts of the plate to spin faster than some...

You made one mistake: You wrote W*m^2*s*kg*K/m^2*kg*J = W*s*K/J On the left hand side you have W*j, but on the right hand side you have W/j. How did you do that? Also, your second eqn should be q = A* k * (T outside - T water) / l so that q has units of W (or j/s), although, that is not really...

Oh, I see. Interesting point of view! Thanks

Out of curiosity, how would you solve the problem with the ice. The ice is a solid undeformable material. As the beaker moves, the ice would stay still. So, how would you solve for the angle?

What is the pressure at the surface equal to? It is usually equal to 1 atm.

Because P is a function of x, z. Therefore, you can write that dP=(dp/dx)*dx+(dP/dz)*dz Why does the negative sign bother you? The above eqn simplifies as follows: 1=(a*rho)dx+(-g*rho)*dz Therefore, the slope is dz/dx=a/g=tan(theta)

You are a little bit confused, and I do not know how to help you. Lets start with the eqn P=-rho * g * h + const What is the meaning of this eqn? It simple related the pressure to the depth. Nothing more than that! Similarly, dP/dz=-rho*g relates the pressure slope to gravity force...

As I said, this equation is not derived from Bernoullis' equation. So you do not need to differentiate with respect to P. Actually, you are right, You need to take a force balance. Are you familiar with the Navier-Stokes equation? This equation is an extension to Bernoullis' equation, when...

Hi Delzac, I did not understand your second question. First of all, the equation dP/dz=-g*rho is not derived from Bernoulli's equation. Bernoullis' equation states that P/rho+g*z+v*2=const. You may consider the equation dP/dz=-g*rho as a constitutive equation. It simply says that as we move...

This is correct! One thing that I missed is that in the 2nd eqn you have the term "k/l". This term has the units of "h", and some people do suggest to set "h=k/l". So, the 2nd eqn is OK. When you write an eqn make sure that the units are in balance. Your first eqn is wrong: Tf - Ti = q * A /...

I thought that my first post had made this clear! I am using http://en.wikipedia.org/wiki/Geodetic_system"

Actually, I do not do any kind of projection. All the points are close to each other, and I could assume that they have the same z. I believe that z is important when you go from one hemisphere to the other. Otherwise, you won't find two different points on the surface of a sphere that have the...

I just realized that I am trying to compare the solution from two different coordinate systems. The only thing I could compare is the distance between two points, but even that would not be the same, due to the enormous radius of the planet.

I hope I am posting in the right section. Up to today I was assuming that Earth is a sphere, and I was using the spherical coordinates to convert longitude/latitude to x/y. But, I wanted to use a more accurate transformation, and I wanted to calculate x/y by considering the actual shape of the...

P is the pressure I made a typo, a*rho=F*rho/m You could set b.c., but it would not change the slope. Remember, that the pressure at the water surface is constant, and equal to 1atm.