2.1 Moment of a Vector About a Point
3
To prove that
M
v
A
=
r
AB
×
v
=
r
AB
0
×
v
=
r
AC
×
v
the following MATLAB com-
mands are used:
simplify(Mv_AB) == simplify(Mv_ABp)
simplify(Mv_AB) == simplify(Mv_AC)
To represent the vectors
r
AB
,
r
AB
0
r
,
v
and
M
v
A
the following numerical data are
used:
x
A
=
y
A
=
z
A
=
0
,
x
B
=
1
,
y
B
=
2
,
z
B
=
0
,
x
C
=
3
,
y
C
=
3
,
z
C
=
0
,
and
k
=
0
.
75.
The numerical values for the vectors
r
A
,
r
B
,
r
C
,
r
Bp
,
v
,
Mv
AB
,
Mv
ABp
, and
Mv
AC
are calculated in MATLAB with:
slist={x_A,y_A,z_A, x_B,y_B,z_B, x_C,y_C,z_C, k};
nlist={0,0,0, 1,2,0, 3,3,0, .75};
rA = double(subs(r_A,slist,nlist))
rB = double(subs(r_B,slist,nlist))
rC = double(subs(r_C,slist,nlist))
rBp = double(subs(r_Bp,slist,nlist))
V = double(subs(v,slist,nlist))
MvA = double(subs(Mv_AB,slist,nlist))