physics... help please!!!! vectors?

Question

the components of a vector can be written (Vx,Vy,Vz). what are the components and length of a vector which is the sum of the two vectors v1 and v2 whose components are (8.0,-3,7,0.0) and (3.9,-8.1,-4.4)????

Answer 1

The sum of a vector v1 and a vector v2: v1 + v2 or v2 + v1 is a vector
whose characteristics are found by either graphical or analytical processes.
The vectors v1 and v2 add according to the parallelogram law: v1+v2 is equal
to the diagonal of a parallelogram formed by the graphical representation of
the vectors (Fig. 1.4(a)). The vector v1 + v2 is called the resultant of v1
and v2. The vectors can be added by moving them successively to parallel
positions so that the head of one vector connects to the tail of the next vector.
The resultant is the vector whose tail connects to the tail of the first vector,
and whose head connects to the head of the last vector (Fig. 1.4(b)).
The sum v1 + (−v2) is called the difference of v1 and v2 and is denoted
by v1 − v2 (Figs. 1.4(c) and 1.4 (d)) .
The sum of n vectors vi, i = 1, . . . , n,
nX
i=1
vi or v1 + v2 + . . . + vn
is called the resultant of the vectors vi, i = 1, . . . n.
The vector addition is:
1. commutative, that is, the characteristics of the resultant are independent
of the order in which the vectors are added (commutativity)
v1 + v2 = v2 + v1.
2. associative, that is, the characteristics of the resultant are not affected
by the manner in which the vectors are grouped (associativity)
v1 + (v2 + v3) = (v1 + v2) + v3.
3. distributive, that is, the vector addition obeys the following laws of
distributivity
v
pX
i=1
si =
pX
i=1
(vsi), for si 6= 0, si 2 R,
s
nX
i=1
vi =
nX
i=1
(svi), for s 6= 0, s 2 R,
where R is the set of real numbers.
Every vector can be regarded as the sum of n vectors (n = 2, 3, . . .) of
which all but one can be selected arbitrarily.

Answer 2

Just add the components of each vector together to get
(11.9,-11.8,-4.4) and then the length is just

sqrt(Vx^2 + Vy^2 + Vz^2)

Answer 3

to find the components you just add the x,y,z values to get
Vx3 =Vx1 +Vx2 = 8.0 +3.9 = 11.9
Vy3 =Vy1 +Vy2 =-3.7 -8.1 =-11.8
Vz3 =Vz1 +Vz2 = 0.0 -4.4 = -4.4
(11.9, -11.0, -4.4)

To find the length, you add the sum of the squares and take the squareroot
(x^2 +y^2 +z^3)^(0.5)
( (11.9)^2 +(-11.8)^2 +(-4.4)^2 )^(0.5)
141.61 +139.24 +19.36)^(0.5)
(300.21)(^(0.5) =17.32656919
or rounded to 17.3

Answer 4

components of that vectors are (11.9,-11.8,-4.4), its lenght is 17.32. components of that vecor are [v1(x)+v2(x)] + [v1(y)+v2(y)] + [v3(x)+v3(y)], lenght= sgrt[v(x)^2 + v(y)^2 + v(z)^2]

Answer 5

It is a concept, just like reality nothing but a concept.