Chapter 2 - Representing Motion

motion

The change in position of an object.

motion diagram

A series of images showing the positions of a moving object at equal time intervals.

particle model

A simpilfied version of a motion diagram in which the object in motion is replace by a series of single pints.

coordinate system

The location of the zero point of the variable you are studying and the direction in which the variable increases.

origin

The point at which both variable have the zero value.

position

The seperation between an object and the origin.

distance

How far away an object is from the origin.

magnitude

The measure of a quantiy in size.

vector

The measure of a quantity in direction.

scalars

A quantity that is just numbers with no direction.

examples of scalars

Direction, time, temperature.

resultant

The vector that represents the sum of any two vectors.

time interval

The difference between two times:
Change in time= T final - T inital

displacement

The change in position:
Change in Displacement= D final - D initial

position-time graph

A horizontal axis and the position data on a vertical axis.

instantanious position

The position at a particular instant.

average velocity

Represented by the slope in a position-time graph:
Average Velocity= Change in Displacement/Change in Time

average speed

This is told by the absolute value of the slope of position-time graph.

instantaneous velocity

The speed and direction of an object in a particular instant.

Equation of Motion for Average Velocity

d=vt+d initial
y=mx+b