DO NOW
• Pick up your clickers and notebooks!!
• You MIGHT want to look over yesterday’s
notes
• You MIGHT also want to copy the Table of
Contents down on page 3 (Notbook
Check?)
Page 17
16
Friday 9/23
16
Motion DOT
Motion Diagrams
Diagram
Write
Study
questions
after
class!
17
KISS, brief notes!
Each slide less than
1 minute!
Record less than 5
to 7 words per slide!
Write Summary after
class!
Picturing Motion: Dot Diagrams
• If you related the position of the runner to the background in each
frame taken in 1 second intervals, you would conclude that the student
is in motion.
• This series of images, taken at regular intervals, creates a motion
diagram for the change in the student’s state of motion.
• Roll a ball along a horizontal
surface, and its velocity is
constant because no component
of gravitational force acts
horizontally
• Drop it, and it accelerates
downward and covers greater
vertical distances each second.
• Motion Diagram Simulation
By noting the distance the object moves in
equal time intervals, you can determine the
object’s state of motion
• A: at rest
• B: moving at a
constant speed
• C: speeding up
• D: slowing down.
Use a dot motion diagram model to draw simplified
motion diagrams
• A: at rest
• B: moving at a
constant speed
• C: speeding up
• D: slowing down.
• Use the dot diagram model to draw a
motion diagram for an object moving at a
constant speed.
• Use the dot diagram model to draw a
motion diagram for an object starting at
rest and speeding up.
• Use the dot diagram model to draw a
motion diagram for an object that starts
from rest, speeds up to a constant speed,
and then slows to a stop.
• Use the dot diagram model to draw a
motion diagram for a wheel turning at a
constant speed. First place the dot at the
hub of the wheel. What would the diagram
look like?
• What would the diagram look like if the dot
were placed on the rim of the wheel?
Dot Diagrams & Vector Quantities
• To determine displacement, velocity, and
acceleration, a coordinate system must be
specified.
• Normally the positive values of x extend
horizontally to the right, and the positive
values of y extend vertically upward.
• The sign of the average velocity depends
upon the chosen coordinate system. The
coordinate systems in a and b are equally
correct
• Color Conventions
– Displacement vectors are green.
– Velocity vectors are red.
– Accelerations vectors are violet
Graphs and motion diagrams are useful in
differentiating constant motion and motion
that is accelerated.
• A speed-versus-time graph
• A distance-versus-time graph