PROJECTILE MOTION PROJECT
Overview and objectives:
You will use your current understanding of motion to make a prediction about where a
ball will land if rolled off a table. After making a prediction, you will confirm your results with
experimental data. You will then extend your calculations to include objects that are launched at
an angel.
Important information:
Equations:
 These are the two most important equations for this project:
Average velocity:
𝑣⃗ =
∆𝑥⃗
∆𝑡
1
Position as a function of time: 𝑥(𝑡) = 2 𝑎𝑡 2 + 𝑣0 𝑡 + 𝑥0
The second equation is in function notation (the left hand side of the equation does not
mean x multiplied by t, it means the position x at the timet). For a free falling projectile
the acceleration a will be gravity, or 9.8 m/s2.
Units:
 Remember, our equations do not work if you mix units. If you are using 9.8 m/s2
for acceleration in the second equations, you can’t use a distance in centimeters
for the initial position (gravity has meters in its units, so you would either need to
convert gravity in to units of cm/s2, or convert you initial position into units of
meters).
 If you are given a choice, always work in SI or MKS units. No feet, yards, or
miles in this class!
Velocity:
 We need a way to produce a consistent initial velocity. Simply rolling the ball off
the table will produce too much variation. Sometimes you will push it harder than
other times. Use the black PVC pipes to create a ramp for your ball. You will
need to keep many variables constant. The angle of the ramp should not change.
You should always release the ball from the same point on the ramp. The end of
the ramp should always be the same distance from the edge of the table.
 In order to determine the initial velocity of the ball you will need to use the
photogate sensors. As the marble is rolling across the table it will have a small
negative acceleration, so to get the most accurate initial velocity of our ball, we
should have the photogates near the edge of the table. Keep the photogates a
fixed distance from each other. You can pick the distance, but about 10 cm works
well. You will need to mess around with LoggerPro or your LabQuest to figure
PROJECTILE MOTION PROJECT
out how to determine the time it took for you ball to pass from one gate to the
next. Typically you’ll need to take the difference between when state (blocked or
unblocked, denoted as states 1 and 0) on each gate changes. If you have a change
in distance and a change in time, you can calculate the average velocity.
Validity:
 If you want the best data, don’t rely on just one measurement. When calculating
the initial velocity of your ball, do at least three trials and average your results.
When you test your prediction with experimentation, do it more than once and
average the distances.
Data:
 Make sure you record all important information. What is the angle of your ramp?
What is the height of the table? What were the results of all your trials, not just
your average?
Report:
Sections:
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



Introduction
o What is the question we are investigating?
o What background knowledge do we have?
Methods
o How will/did you conduct your experiment/gather data? What materials did
you use? Why did you do things this way?
Data
o Put your data in a well organized table. Include units. Label table correctly.
Calculations
o Clearly show your work. Have at least one full example of calculations that
you repeat (you do not need to show the same calculation each time). Include
units in your set-up and final answer, but not throughout all your steps.
Calculations should be separate from blocks of text and centered.
Results/Discussion
o What did you find and what does it mean? Answer your initial questions and
support your answer with data from your experiment. Discuss ways that you
could use this knowledge, or further experiments you could conduct. Discuss
any sources of error.
Important Formatting Notes:
 Use a standard 12 point font like Times New Roman.
 Number tables and figures (graphs and pictures) in chronological order.
 Label tables and figures with descriptive headings or a summary sentence.
 Label tables above and figures below.
 Italicize variables such as x or a.
PROJECTILE MOTION PROJECT

When showing calculations or steps in solving a problem, show the steps separate from
the text, centered in the page. For example, if I was to describe how to solve 5x – 1 = 24
for x, I would show it as follows:
We begin with the following equation:
5x – 1 = 24
First add one to each side of the equations to get the following:
5x = 25
Next divide both sides of the equation by 5 to arrive at our final result:
x=5