**HP Prime: Center of Mass - Matrix Representation**

The HP Prime
program CENTERMTX calculates the center of mass of the matrix M, where M
represents the body. The entries of M
represents an array of molecules, each with assigned weights. It is possible that the center of mass is
located outside of the body.

Note: If gravity affects the particles equally,
then the center of mass & center of gravity are identical.

Formulas:

Xc = ∑(x *
m)/∑m

Yc = ∑(y *
m)/∑m

**HP Prime: CENTERMTX**

EXPORT
CENTERMTX(m)

BEGIN

// Center of Mass: matrix

// Matrix of mass

LOCAL s,tm,rt,ct,r,c;

// in MAKEMAT I=row,J=col

s:=SIZE(m);

r:=s(1);

c:=s(2);

// Total Mass

tm:=TRN(m*MAKEMAT(1,c,1))*

MAKEMAT(1,r,1);

tm:=tm(1,1);

// Row Total

rt:=TRN(m*MAKEMAT(I,c,1))*

MAKEMAT(1,r,1);

rt:=rt(1,1);

// Column Total

ct:=TRN(TRN(m)*MAKEMAT(I,r,1))*

MAKEMAT(1,c,1);

ct:=ct(1,1);

// center

RETURN [[rt/tm,ct/tm]];

END;

Example: Locate the center of mass of the following
body.

The center of
mass: [[ 2.08333333333, 2 ]]

Eddie

This blog is property
of Edward Shore. 2015.

Hi Eddie,

ReplyDeleteThank you for your blog. I really appreciate your articles on the HP Prime, especially with the lack of info I have about this calculator.

I have used it lately for my Fluid Dynamics course and I am having trouble solving systems with the Solve app. Specifically, systems involving the Colebrook equation. I can't post it here because it won't let me attach photos, so her is the link to its Wiki page:

http://en.wikipedia.org/wiki/Darcy_friction_factor_formulae#Compact_forms

The problem is that the calculator either crashes or can't solve. Am I doing something wrong? Is there another way of solving equation systems?

Thank you in advance

Castro,

DeleteYou can email me the screen shot at ews31415@gmail.com.

Eddie