Key Terms

acceleration
the rate at which velocity changes
average speed
distance traveled divided by time during which motion occurs
average velocity
displacement divided by time over which displacement occurs
dependent variable
the variable that changes as the independent variable changes
displacement
the change in position of an object against a fixed axis
distance
the length of the path actually traveled between an initial and a final position
independent variable
the variable, usually along the horizontal axis of a graph, that does not change based on human or experimental action; in physics this is usually time
instantaneous speed
speed at a specific instant in time
instantaneous velocity
velocity at a specific instant in time
kinematics
the study of motion without considering its causes
magnitude
size or amount
position
the location of an object at any particular time
reference frame
a coordinate system from which the positions of objects are described
scalar
a quantity that has magnitude but no direction
speed
rate at which an object changes its location
tangent
a line that touches another at exactly one point
vector
a quantity that has both magnitude and direction
velocity
the speed and direction of an object