college physics-uark test 1

motion

the change of an objects position or orientation with time

trajectory

the path along which an object moves, which might be straight or curved

motion diagram

showing an objects positions at several equally spaced instants of time

operational definitions

the concepts are defined in terms of particular procedures or operation

particle

an object that can be represented as a mass at a single point in space

model

a simplification of reality; allow us to focus on the important aspects of a phenomenon by excluding those aspects that play only a minor role

particle model

a simplification in which we treat a moving object as if all of its mass were concentrated at a single point

one-dimensional

the motion of an object that can move only along a straight line

position

location at a particular instant in time

origin

fixed reference point

coordinate system

an origin and an axis marked in both the positive negative directions

coordinate

the symbol that represents a position along an axis

displacement

a change of position

time intervals

changes in time

uniform motion/constant velocity motion

objects moving along a straight line at a constant speed, objects that are neither speeding up nor slowing down; straight-line motion in which equal displacements occur during any successive equal-time interval

velocity

displacement (change in position) divided by time; tells us both an objects speed and direction

significant figures

a digit that are reliably known

conversion factor

a ratio of values equal to 1

order-of-magnitude

one sig fig estimate or calculation

scalar equality

physical quantity is described by a single number (with a unit)

vector quantity

a quantity that has both a size (how far and fast?) and a direction (which way)

magnitude

the size or length of a vector; can not be neg

displacement vector

a quantity that has both a magnitude (how far) and a direction

velocity vector

what we use to represent the velocity of an object

kinematics

the name for the mathematical description of motion

position-verse-time graph

a continuous curve that shows an object's position as a function of time

speed is the ____ of the velocity vector

magnitude

the slope of an object's position-time graph is the objects ___ at that point in the motion

velocity

____ ∆x is equal to the area under the velocity graph during interval ∆t

displacement

instantaneous velocity

an object's velocity--a speed and a direction---at a specific instant of time (t)

acceleration

is the slope of its velocity verse time graph

pictorial representations

shows all of the important details that we need to keep track and will be very important in solving motion problems

free fall

if an object moves under the influence of gravity only, and no other forced

any two objects in free fall have____

the same acceleration...no matter the mass

scalar quantity

is the magnitude of a vector, cannot be negative

net displacement

you find this when you add vectors

resultant vector

the sum of two vectors

graphical addition

tip-to-tail method used while adding vectors

parallelogram rule

vector sum can be found as the diagonal of the parallelogram defined by the vectors being added together

zero vector

the product is a vector with zero length and zero magnitude

uniform circular motion

moving at a constant speed, but in a continuously changing direction

Cartesian coordinates

rectangular grid with perpendicular axes

component vectors

vectors parallel to the axes

decomposed or resolved

breaking a vector down into its component vectors

component

single number (or scalar) that describes a component vector

g

free fall acceleration

limiting cases

cases in which physics is clear and results can be easily compared

projectile motion

two dimensional free fall motion

projectile

an object that moves in two dimensions under the influence of gravity and nothing else

launch angle

the angle of initial velocity above the horizontal

centripetal acceleration

an acceleration that always points directly toward the center of a circle