Vectors Flashcards
Vectors
Directional arrows that describe an objects motion and magnitude
Naming vectors
[OriginPoint][EndPoint]
Line over head
ie PQ
Scalar-vector multiplication
Multiplying the vector magnitude by a constant (c)
Endpoint (x,y,z) becomes
(cx,cy,cz)
Scalar multiple
A vector whose magnitude is multiplied by a contant
Parallel vectors
Vectors that are scalar multiples of eachother
Equal vectors
Vectors of the same direction and magnetude
Not necessarily the same position
Zero vector
A vector component with no length
Vector addition
u+v
Reposition the vectors ‘u’ and ‘v’ so that they form two sides of a triangle
Use c^2=a^2+b^2, one at a time for multiple vectors
Add endpoint vx to ux, vy to uy, and vz to uz
Vector subtraction
u-v
Change the direction of vector ‘v’
Reposition the vectors ‘u’ and new ‘v’ so that they form two sides of a triangle
Use c^2=a^2+b^2
Subtract endpoint vx from ux, vy from uy, and vz from uz
Position vectors
Vector with its head at (0,0)
Standard position
(0,0)
The general starting point for object motion
X-component
The vector that measures how far the object moves in simply the x-direction, if y and z were ignored
Y-component
The vector that measures how far the object moves in simply the y-direction, if x and z were ignored
Z-component
The vector that measures how far the object moves in simply the z-direction, if y and x were ignored
Vector magnetude
The ‘length’ of the vector, typically a representation of acceleration
Denoted |PQ|
Use Pythagorean theorem
|PQ|=√[(x-xi)^2+(y-yi)^2+(z-zi)^2]
Writing vector coordinates
Where u1is the origin point for the vector and u2 is the vector head
Vector head
End-point of the vector
Origin point
Point at which the vector begins
Unit vector
Any vector with a magnitude of 1
Right hand coordinate system
Graph ‘z’ up, ‘y’ right, and ‘x’ diagonal towards you
Vector magnetude 3D coordinate plane
r=√[(x-xi)^2+(y-yi)^2+(z-zi)^2]
Dot product
Product of the magnitudes of each vector and the ‘cos’ of the angle between the two vectors, is equal to the sum of their component products
u⊙v=|u||v|cosθ=(ux)(vx)+(uy)(vy)+(uz)(vz)
Orthogonal vectors
Vectors whose dot product is zero
u⊙v=0
Yields perpendicular vectors
Projections
Proj=|u|cosθ(v/|v|)
Also equals
v[(u⊙v)/(v⊙v)]
Work
Dot product of the force vector and the traveling vector (in which the object actually travels, gives the angle measure if you have the magnitudes
W=F⊙d=|F||d|cosθ
Cross product
|u x v|=|u||v|sinθ
Matrix representation of cross product
i. j. k.
u. = u x v =|j and k|i+|i and k|j+|j and i|k
v
Torque
Cross product of force and radius, outward pressure due to force on a plane, think of tightening a wrench (torque is the force pushing a screw in or out of a hole)
r x F
Vector-valued functions
Expressing an algebraic curve in space with three functions i,j,k
v(t)=[f(t)]i+[g(t)j+[h(t)]k
Limits of vector-valued functions
Lim t→a v(t)=[f(t)]i+[g(t)j+[h(t)]k
Tangent vector
Basically the derivative if the vector valued function
When v(t)=[f(t)]i+[g(t)j+[h(t)]k,
Then
v’(t)= [f’(t)]i + [g’(t)j + [h’(t)]k
Unit Tangent Vector
Gives the direction but not the length of the tangent vector at point-t T(t)=v'(t)/|v'(t)| For v(t)= [f(t)]i + [g(t)j + [h(t)]k
Integral of a vector valued function
When v(t)=[f(t)]i+[g(t)j+[h(t)]k, ∫v(t)= [∫f(t)]i + [∫g(t)j + [∫h(t)]k
Uniform motion
Motion in a straight line
Arc Length for Vector functions
L=∫√[f’(t)^2+g’(t)^2+h’(t)^2]dt = ∫|v’(t)|dt
Curvature
A measure of how quickly the direction of the curve changes over a given interval
Given as K=|dT/ds|
Where T= ∂v/|∂v|
And ‘s’ equals arc length over a set interval