### Key Terms

- anticommutative property
- change in the order of operation introduces the minus sign

- antiparallel vectors
- two vectors with directions that differ by $180\text{\xb0}$

- associative
- terms can be grouped in any fashion

- commutative
- operations can be performed in any order

- component form of a vector
- a vector written as the vector sum of its components in terms of unit vectors

- corkscrew right-hand rule
- a rule used to determine the direction of the vector product

- cross product
- the result of the vector multiplication of vectors is a vector called a cross product; also called a vector product

- difference of two vectors
- vector sum of the first vector with the vector antiparallel to the second

- direction angle
- in a plane, an angle between the positive direction of the
*x*-axis and the vector, measured counterclockwise from the axis to the vector

- displacement
- change in position

- distributive
- multiplication can be distributed over terms in summation

- dot product
- the result of the scalar multiplication of two vectors is a scalar called a dot product; also called a scalar product

- equal vectors
- two vectors are equal if and only if all their corresponding components are equal; alternately, two parallel vectors of equal magnitudes

- magnitude
- length of a vector

- null vector
- a vector with all its components equal to zero

- orthogonal vectors
- two vectors with directions that differ by exactly $90\text{\xb0}$, synonymous with perpendicular vectors

- parallel vectors
- two vectors with exactly the same direction angles

- parallelogram rule
- geometric construction of the vector sum in a plane

- polar coordinate system
- an orthogonal coordinate system where location in a plane is given by polar coordinates

- polar coordinates
- a radial coordinate and an angle

- radial coordinate
- distance to the origin in a polar coordinate system

- resultant vector
- vector sum of two (or more) vectors

- scalar
- a number, synonymous with a scalar quantity in physics

- scalar component
- a number that multiplies a unit vector in a vector component of a vector

- scalar equation
- equation in which the left-hand and right-hand sides are numbers

- scalar product
- the result of the scalar multiplication of two vectors is a scalar called a scalar product; also called a dot product

- scalar quantity
- quantity that can be specified completely by a single number with an appropriate physical unit

- tail-to-head geometric construction
- geometric construction for drawing the resultant vector of many vectors

- unit vector
- vector of a unit magnitude that specifies direction; has no physical unit

- unit vectors of the axes
- unit vectors that define orthogonal directions in a plane or in space

- vector
- mathematical object with magnitude and direction

- vector components
- orthogonal components of a vector; a vector is the vector sum of its vector components.

- vector equation
- equation in which the left-hand and right-hand sides are vectors

- vector product
- the result of the vector multiplication of vectors is a vector called a vector product; also called a cross product

- vector quantity
- physical quantity described by a mathematical vector—that is, by specifying both its magnitude and its direction; synonymous with a vector in physics

- vector sum
- resultant of the combination of two (or more) vectors