Community Profile

# Are Mjaavatten

### Mjaavatten Consulting

271 total contributions since 2015

I have a MSc in physics from the University of Oslo and a PhD in control engineering from NTNU in Trondheim (mainly modelling, I am not much of a control engineer). My main interests are mathematical modelling, numerical methods, and thermodynamics. I worked in the petroleum and chemical process industries for some 35 years and I am now semi-retired

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Solution for system of two non linear equation
You can rewrite you equations as (Nd-x-y)-a*(x*(x+y)) = 0 (Nd-x-y)*(No-y)-b*(y*(x-y)) = 0 where x = Nd, y = Nonegative, a = ...

alrededor de 16 horas ago | 1

| accepted

Problem of erf when using fmincon
Your problem has infinitely many solutions. Whenver x(1)-x(3) = 1 and x(2)-x(4) = 1, fun = 0, which is the minimum value possib...

10 días ago | 0

how to Nonlinear equations?(two variables)
Although R1 and R2 are nonlinear finctions of t, your equations are linear in x. So you write the equations on the form A(t)*...

23 días ago | 2

| accepted

How to count number of times a number appears in column B based on column A
letters = 'ABAACD'; numbers = [1,2,2,1,1,3]; uniqueletters = unique(letters); uniquenumbers = unique(numbers); n = length(un...

25 días ago | 0

| accepted

Submitted

nistdata(species,T,p)
Create tables of thermophysical properties for gases

Van der Waals equation - Newton's method
In your code, newton_ndim does not know the value of T and so cannot call fun(X,T). You can probably fix this by defining an in...

2 meses ago | 0

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Submitted

Curvature of a 2D or 3D curve
Calculates the local radius of curvature as well as the cumulative arc length and the curvature vector along a 1D curve in 2D or...

Solved

How Far Can You Throw Something?
As you probably learned in your high school physics class, throwing an object at a 45 degree angle will give you the maximum ran...

3 meses ago

Solved

Calculate the height of an object dropped from the sky
Assume that an object is dropped from 1000 meters above the surface of the earth at time t=0. The object is dropped such that t...

3 meses ago

Solved

Distance of the centroids of the balls
Given *n* balls of radius *r* and the vector *p (nx3)* with all position *(x,y,z)* of the balls, return the symmetric matrix *A ...

3 meses ago

Solved

Calculate compression ratio of engine
Calculate compression ratio of engine given compression volume of cylinder(Vc), piston stroke(s) and valve diameter(d)

3 meses ago

Solved

Elastic Collision 001: 1-D
Elastic Collision of two particles. <http://en.wikipedia.org/wiki/Elastic_collision wiki Elastic Collision> Solve Conservat...

3 meses ago

Solved

Center of mass
Given a matrix M(m,n), where m is the number of vertices of the geometrical element and n is 2 or 3 (2D-plane figure or 3D-solid...

3 meses ago

Solved

center of mass
R is a given matrix with size [n,2]. R(i,:) is interpreted as the 2D-position of a mass point with mass i. Calculate the center ...

3 meses ago

Solved

Determine if a four bar mechanism is of Grashof type
A four bar mechanism is composed of four links. if s is the smallest link, l the longest and p,q are the length of the other lin...

3 meses ago

Solved

Find the jerk
No, it's not the author of this problem... Jerk is the rate of change in acceleration over time of an object. So, if given t...

3 meses ago

Solved

Juggling
There is a notation system for <http://en.wikipedia.org/wiki/Juggling jugglers> called <http://en.wikipedia.org/wiki/Siteswap si...

3 meses ago

Solved

Bernoulli's Equation
Bernoulli's equation states that for an incompressible fluid the following summation is constant across the flow: v^2/2 + g*z + ...

3 meses ago

Solved

What gear ratio does the cyclist need?
A cyclist (perhaps including our famed Codysolver the cyclist <http://www.mathworks.com/matlabcentral/cody/players/1841757-the...

3 meses ago

Solved

Mechanical Advantage of a Gear Train
Calculate the mechanical advantage of a gear train. The mechanical advantage of a gear couple is given by MA = T_o/T_i where ...

3 meses ago

Solved

Kepler's Equation
Solve <http://en.wikipedia.org/wiki/Kepler's_equation Kepler's Equation>. Note that the solution is rounded down to 5 decima...

3 meses ago

Solved

Energy of an object
Calculate the total mechanical energy of an object. Total Energy= Potential energy + Kinetic energy P.E.=m*g*h K.E.=1/2...

3 meses ago

Solved

Bouncing disk
A disk is placed in a rectangular room with dimensions a and b in a point with coordinates x0 and y0. The disk is given a startu...

3 meses ago

Solved

jogging?
Imagine x-y coordinate system and you are at the origin and your partner is on the x-axis at some small distance (d) away from y...

3 meses ago

How do I solve system of equations?
If I understand you correctly, your system consist of 128 eqations. a and b are arrays of 64 unknowns each. You must then solv...

3 meses ago | 0

| accepted

Join repeated continuous elements of a vector
in = [1 1 1 2 2 3 6 6 6 1 1 1 4 4 4 2 2 2 6 4 4]; i = 1; count = 1; out = []; a = in(1); while i < length(in) i = i+1; ...

3 meses ago | 0

Submitted

Thermo: Compressible real gas tool
A Matlab object for calculating consistent thermodynamic properties of real gases

Solved

Mechanics 1
I thought I would make a mechanics problem for all those physics lovers out there. Imagine two solid, rigid spheres B1 and B...

3 meses ago

Solved

Find the palindrome
Given the string a, find the longest palindromic sub-string b. So when a = 'xkayakyy'; you should return b = 'kayak';

3 meses ago

Solved

What is the next step in Conway's Life?
Given a matrix A that represents the state of <http://en.wikipedia.org/wiki/Conway's_Game_of_Life Conway's game of Life> at one ...

3 meses ago