# Motion

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```					Standard Strand 1: Motion
1. An object in motion changes
position relative to a reference
point.
2. Speed measures how fast
position changes.
3. Acceleration measures how fast
velocity changes.
Warm-up:
   Choose an object in the class that is easy
to recognize.
   Without writing what it is, write directions
to the object from your seat.
   Share your directions with your tablemate.
Can he/she identify the original object?
   Change your directions until your partner
locates your object.
   Can you locate your partner’s object?
Modify the directions until you can.
JOURNAL(continued) :
   What is position?

   How do you describe a position?

   How would your describe motion in terms
of position?
Key Terms:
   Direction            Motion

   Displacement         Velocity

   Position             Slope

   Acceleration         Vector

   Speed                Reference point
– Average
– Instantaneous      Magnitude
– Constant
Motion
   Is a change in position with time (meaning
there is time interval involved - not
instantaneous)

   Is observed relative to a reference point:

– Are you in motion sitting quietly in your seat?
• From the viewpoint of the teacher? Your table
partner?
• From a viewpoint of an observer on the International
Space Station?
Reference point:
 Point from which motion is
detected/compared
 The most common reference point is the
Earth
 Motion is said to be relative to a reference
point
 Examples:
– You are driving in a car. The driver is not
moving in comparison to you (RP1), but is
moving (as are you) relative to a person (RP2)
standing on the street who sees the change in
position
Reference Point Activity
   The teacher tosses the ball in the air.
Describe the motion of the ball from the
teacher’s and the your position as
reference points.

   The teacher walks across the room
tossing a ball up and down. Describe the
balls motion - From both reference points.
What other terms are involved in
motion?
   There is a change in position over time
which implies a distance has been
covered….Distance from position 1 to 2, 3,
4 and so on…..

   There is a time interval.

   What is the quantity known as distance/
unit time?
Speed
   Distance traveled over time

   What is average speed?

   What is constant speed?

   What is instantaneous speed?

   How would you graph speed?
Speed = distance/time
   Our variable are: distance and time

   Which is the “X” axis variable?
– Manipulated variable (independent
variable)

   Which is the “Y” axis variable?
D
i        What is slope?
s
t
a
n
c
X
e
Y
(Meters)

Time (seconds)
Slope
   The slope of a line is calculated by
dividing the change in Y (distance
between the Y’s) by the change in X

Y        Yf - Yi         RISE
=               =
X        X f - Xi       RUN
Slope : Rise (Y)/Run (X)
   The slope of a line on a distance/time graph
indicates the speed (d/t) of the object.

   Average speed: over time interval (speed/slope
changes)

   Instantaneous speed: at a particular point

   Constant speed: straight line

   Slope = 0, no motion

```
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