Recent content by niko2000

Hi, I am completing the study of telecommunications. As I've lost some lecture notes and I like to keep references on my bookshelf I am looking for a good book about Electromagnetism, electromagnetic radiation and radio communications. From the comprehensive online offer it is not easy to...

Hi, I am trying to calculate the power of a reflected electromagnetic field and can't find a physical explanation for a given solution. I've noticed the following example: The Plane has a radar for altitude measurement which emmits the power Ptx at the frequency ftx. Calculate the power...

How can you determine the type of motion by integrating the graph? The goal is to determine the type of movement by analizing graph - whether it is walk, run, fall... I wrote about the concept here: http://mypetprojects.blogspot.com/

Hi, I would like to calculate the used energy with the accelerometer. Does anyone know how to calculate the used energy (work) from acceleration and body mass?

Any idea about how determine body movement upon the accelerations? Hi, I am trying to implement an algorithm which would determine the person's activity upon the received acceleration measurement data. I am measuring the accelerations using accelerometer sensors on mobile phones and send...

The equation doesn't change. You can get this equation by wrighting a sum of currents on - connection. If you add a load resistor V0 doesn't change thus you can write Uy/R1+V0/R2 = 0 and you get the same equation.

Hi, I am approaching the end of my current study of electrical engineering - telecommunications. The world of airplanes and flying machines has also been fascinating me for some time now. But for now this is almost entirely unknown field to me. I would be very happy if I could work somewhere in...

Hi, I am currently 3rd year electrical engineering (telecommunications department). I am really interested in it and I am already thinking about the career. I have pretty high ambitions so I would like to get some advices about the best way to success in engineering work. I am thinking about...

Hi, Let's tie a sphere, drop it into a water and trawl it with a boat. How do we calculate the angle between a vertical line and rope? Actually I don't know much about aerodynamics and hydrodynamics so I don't know how drag force is calculated from shape, mass and speed of an object. Recently...

If we think about the relations between quantities: Let's look an angle between vertical line and the man on the rope and we assume equilibrium at x=0. A=angle, v=speed on x direction, k and g are some coefficients dA(t)/dt=k*A(t)-g*v(t) My explanation: If the angle is greater, the angle is...

Hi, I am trying to do a model for a ropewalk. I would like to describe it with two first order differential equations. If we consider a person walking on a rope there are two quantities changing; the speed of a rope in horizontal direction and the angle of a person. I have to write this in a...

Hi! I am doing a simple mathematical model of an airship. I need the data for air temperature, density and pressure for different altitudes. Could anyone give me any web address where I could find these data? I am not native to this field, so I don't know how do these quantities change with...

We were calculating Lame's coeficients for some coordinate system. We had these data: x=a*Cosh[B]*Sin[P]*Cos[F] y=a*Cosh[B]*Sin[P]*Sin[F] z=a*Sinh[B]*Cos[P] The first coeficient (let's call it f1): f1=Sqrt[(dx/dB)^2+(dy/dB)^2+(dz/dB)^2] The second...

a*Sqrt[(Cos[x])^2+(Sinh[y])^2] is what I've got on paper and that is not related to the first problem. The first problem was that mathematica couldn't simplify this: Sqrt[a^2*(Cosh(x))^2*(Sin(y))^2]

What is true if that's not true?