Download Chapter 2 – Motion Section 1 – Describing Motion Reference Point

September 15, 2016
Chapter 2 – Motion
Section 1 – Describing Motion
Reference Point – starting position
Motion – change in an object’s position relative to a
reference point
Frame of Reference – a coordinate system in which the
position of the object is measured
> Graph
Glenco Physical Science 2012
September 15, 2016
Change in Position
Meter(m) – SI unit for distance
Distance – how far traveled
Displacement – the distance and direction of the object’s
change in position
Sample problem:
Steve runs 75 m west and then turns around and runs 50 m
east. How far is he from his starting point? How far did he
run?
September 15, 2016
Adding Displacements
Always add head to tail...
http://www.motherjones.com/environment/2011/10/ringling-bros-elephant-abuse
1.
Same direction
2.
Opposite directions
3.
Not same nor opposite
September 15, 2016
Speed – the distance an object travels per unit of time
d
s=
t
A bike traveling at a constant speed covers a distance of
500m in 75s. What is the bike’s speed?
Constant speed – traveling the same rate for a given period
of time
Changing speed – speed varies over the trip
Average speed – total distance traveled divided by the total
time
Instantaneous speed – how fast the object is moving at a
single point in time
Mini lab page 48
September 15, 2016
Glenco Physical Science 2012
What is represented on the x-axis?
What is represented on the y-axis?
How is speed represented on this graph?
*Remember that a constant slope = a constant speed
September 15, 2016
Homework:
P 47 # 1-3
P 50 # 6-10