# Graph Matching

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14 Νοε 2013 (πριν από 4 χρόνια και 6 μήνες)

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Abington Heights High School

Science Department

Physics L
-
2

Laboratory Exercise

Graph Matching

1

Graph Matching

One of the most effective methods of describing motion

is to plot graphs of distance and
velocity
vs
. time. From such a graphical representation, it is possible to determine in what direction an
object is going, how fast it is moving, how far it traveled, and whether it is speeding up or
slowing down. In this experiment, you will use a Motion Detector to

determine this information
by plotting a real time graph of
your

motion as you move across the classroom.

The Motion Detector measures the time it takes for a high frequency sound pulse to travel from
the detector to an object and back. Using this round
-
t
rip time and the speed of sound,
Logger Pro

can determine the distance to the object; that is, its position. It can then use the change in
position to calculate the object’s velocity and acceleration. All of this information can be
displayed in a graph. A
understand the concepts of kinematics.

walk back and forth
in front of
Motion Detector

OBJECTIVES

Predict, sketch, and test distance
vs
. time kinematics graphs.

Predict, sketch, and test velocity
vs
.
time kinematics graphs.

MATERIALS

GO!Motion

Laptop

meter stick

Logger Pro

Abington Heights High School

Science Department

Physics L
-
2

Laboratory Exercise

Graph Matching

2

Procedure

1.
Place the Motion Detector so that it points toward an open space at least 4

m long. Use short

strips of masking tape on the floor to mark
the origin and the 1

m, 2

m, and 3 m distances
from the Motion Detector.

2.

Use the black cable to connect the Go!Motion and the
l
aptop.

3.
Open Logger Pro on the laptop.
Practice collecting data by pressing the start button on the
Logger Pro screen and

moving back and forth in front of the Go!Motion
.

Distance
vs
. Time Graph Matching

4.

Choose File; Open;
_Physics with Computers
.

5
.

In the

open

folder
there

are two saved distance versus time graphs; “
01b Graph Matching

and “
01
c

Graph Matching

6
.

As a group,
sketch a copy of th
ese

graph
s

and
w
rite down ho
w you would walk to produce
the

target graph
s
.

Remember the vertical axis represents distance, the horizontal axis
represents time.

7
.

To test your prediction, choose a starting position and
stand at th
at point. Start data collection
by pressin
g “Go” on the LoggerPro screen.
When you hear the Motion Detector begin to
click, walk in such a way that the graph of your motion matches the target graph on the
laptop

screen.

8
. If you were not

successful, repeat the process until your motion closely m
atches the graph on
the screen.
Sketch the graph with your best attempt.

9
. Each group member will attempt to match
both graphs
.

Velocity
vs
. Time Graph Matching

10.

In the
same

folder

as above,
there are two saved velocity versus time graphs; “
01
d

Graph
Matching
” and “
01
e

Graph Matching

11.

As a group, sketch a copy of these graphs and write down how you would walk to produce
the target graphs. Remember the vertical axis represents
velocity, the horizontal axis
represents time.

12. To test your prediction, choose a starting position and stand at that point. Start data collection
by pressing “Go” on the LoggerPro screen. When you hear the Motion Detector begin to
click, walk in s
uch a way that the graph of your motion matches the target graph on the
laptop screen.
It will be more difficult to match the velocity graph than it was for the
distance graph.

13.

If you were not successful, repeat the process until your motion closely ma
t
ches the graph on
the screen.

14.

Each group member will attempt to match
both graphs

16.

Remove the masking tape strips from the floor.

Abington Heights High School

Science Department

Physics L
-
2

Laboratory Exercise

Graph Matching

3

ANALYSIS

Distance
vs
. Time Graph Matching

1.

Explain the significance of the slope of a distance
vs
. time graph. Inc
lude a discussion of a)
positive and b) negative slope.

2.

What type of motion is occurring when the slope of a distance
vs
. time graph is zero?

3.

What type of motion is occurring when the slope of a distance
vs
. time graph is constant?

4.

What type of mo
tion is occurring when the slope of a distance
vs
. time graph is changing?

Velocity
vs
. Time Graph Matching

5.

What type of motion is occurring when the slope of a velocity
vs
. time graph is zero?

6.

What type of motion is occurring when the slope of a
velocity
vs
. time graph is not zero?

GRAPHS

1.

Sketch
s
, and write how you would obtain
them. Sketch in
your best attempt at matching the graph.

2.

Sketch your velocity versus time graphs, and write how you would obtain

them. Sketch in
your best attempt at matching the graph.