Name ______________________________
Ms. Sabbatino
Date ___________
Period _________
Lab #4a:
Representing Acceleration on a Distance vs. Time Graph
Goals:
- To determine the shape of a distance vs. time graph for an accelerating object.
- To determine the instantaneous velocity of an accelerating object.
Background:
In order to successfully complete this lab, you need to understand how a ticker tape timer
works. The ticker tape timer has a ‘tapping’ arm that taps at a given number of taps per second.
There is also a carbon paper disk under the tapping arm. If you place the white tickertape under
the carbon paper and pull, the arm will create a series of marks on the ticker tape. This is an
example of a particle model of motion. Our ticker tapes tap at 60 times per second.
On a distance vs. time graph, the slope of the graph represents the speed of the object
(you know this from your buggy lab). For an object at a constant velocity, the slope of a line is
easily calculated using the slope formula. For an object undergoing acceleration, the velocity is
constantly changing, which means the slope is constantly changing. In order to find the
instantaneous speed of an object, you will need to find the slope of a line tangent to the graph.
The slope of this tangent line will represent the speed of the object at that instant in time.
Predictions
- What do you think the tape for an object moving at constant speed would look like? Sketch the
dots on the section of the tape below.
- If you were to then graph a position vs. time graph for this ticker tape, what do you think it
would look like? Sketch it below.
- What do you think the tape for an accelerating object would look like?
- If you were to then graph a position vs. time graph for this ticker tape, what do you think it
would look like? Sketch it below.
Materials:
- 500g weight
- Tape
- Ticker tape and timer
- Ring stand
- Old text book
- Meter stick
- Colored Pencils
Lab set up:
Draw and LABEL exactly what your lab set up looked like.
Procedure
 Place the ring stand on the desk, and mount the tickertape timer to the top.
 Rip off a piece of ticker tape that is about as long as the distance from the floor to
the timer.
 Place the white tickertape below the carbon disk (make sure the dark blue/black
side is facing down.)
 Tape the 500g weight to the end of the ticker tape.
 Turn on the timer then release the weight.
 Check the tape to make sure the dots are visible along the entire tape. Check with
me to make sure.
 Locate the starting streak and mark off the end of that as your starting point
(again, check with me to make sure you are using the correct point)
 Using a ruler/meter stick, measure and record the distance in cm to each dot from
the starting point!
 Using this data, graph a distance vs. time graph.
Data:
time (s)
Part I
distance ( cm )
.033
.6
.066
2.7
.1
5.8
.133
10
.166
15
.2
21
.233
28
.266
35.7
.3
44.6
.333
54.5
.366
65.
.4
77
.433
89.4
.466
102.5
.5
116.7
.533
132.5
.566
149.5
Analysis:
□ Create a distance vs. time graph and draw a BEST FIT LINE/CURVE. DO NOT
CONNECT THE DOTS!!!! (ask for help if you need it!!!)
□ Examine your curve and choose seven points that are well defined (either actual
data points or places where your line passes directly through the grid lines on the
paper) and circle them.
□ Reread the background information dealing with instantaneous velocity.
□ Using a different colored pencil, at each of your circled points draw a line that is
tangent to your graph.
o THESE LINES SHOULD NOT CROSS OVER TO THE LEFT SIDE
OF YOUR GRAPH!!!!!!!
Conclusion:
1. Describe the shape of a distance vs. time graph for an accelerating object.
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2. What does the slope of this distance vs. time graph represent?
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