Thread: linear equations in matlab

Consider a point body of mass hung from a ceiling on two ropes which form the angles α and β to the horizontal. Tension forces and in the ropes are then determined by the solution of the following system of linear equations

-T1 cos 30 + T2 cos 45 = 0

T1 sin 30+ T2 sin 45 = mg

where g=9.80665ms-2 is the acceleration due to gravity

Write a script M-file which computes the tension forces T1and T2when m=20kg and alpha=30 and beta=45 degrees

ive been told to represent this system in matrix form, but im not sure how to.....

can anyone help?

thanks

Originally Posted by saha01

Consider a point body of mass hung from a ceiling on two ropes which form the angles α and β to the horizontal. Tension forces and in the ropes are then determined by the solution of the following system of linear equations

-T1 cos 30 + T2 cos 45 = 0

T1 sin 30+ T2 sin 45 = mg

where g=9.80665ms-2 is the acceleration due to gravity

Write a script M-file which computes the tension forces T1and T2when m=20kg and alpha=30 and beta=45 degrees

ive been told to represent this system in matrix form, but im not sure how to.....

can anyone help?

thanks

CB

delete

Originally Posted by CaptainBlack

CB

i cant seem to insert [ t1 and t2] into matlab, it says undefined function, how should i change this?

You are solving for , so you write

where .

Originally Posted by lvleph

You are solving for , so you write

where .

yes i know that, but the problem im having is that when i type into matlab [ T1 T2], it says T is an undefined function or variable.

Can you post your code then?

Originally Posted by lvleph

Can you post your code then?

T=A\b

A=[-cos(30) cos(45)
sin(30) sin(45)]


m=20
g=9.80665

b=[0 m*g]

when i type this in i get

??? Error using ==> mldivide
Matrix dimensions must agree.

Your code should be in this order

Code:

A=[-cos(30) cos(45)
sin(30) sin(45)]


m=20
g=9.80665

b=[0 m*g]

T=A\b