# Describing Constant Velocity

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```					Physics 11
Describing Constant Acceleration Lab Activity
Purpose:

   Describe constant acceleration using a motion diagram, graphical and mathematical analysis.
   Develop an operational definition of constant acceleration.

Outcomes Met:

   Identify the frame of reference for a given motion and to distinguish fixed and moving frames.
   Identify and investigate questions that arise from practical problems and issues involving motion.
   Analyse word problems, solve algebraically for unknowns, and interpret patterns in data.

Procedure:

1. Use an inclined air table, spark timer and sheet of paper to generate a motion diagram for a puck
moving at constant acceleration.
2. Using a ruler, determine the interval on the motion diagram that displays constant acceleration.
3. Mark the first distinguishable dot in that interval as “0” (or reference point).
4. Measure the distance from “0” to the next dot.
5. Measure the distances to each successive dot from the reference point. Be sure to account for
the precision of your ruler by using the appropriate number of significant digits.
6. Create a position-time table of your measurements.

Data Analysis:

1. Create a position-time graph of your data. Be sure to properly scale and label the axes. Entitle
2. Use a flexible ruler (or a steady free hand) to draw the curve of best fit that appropriately models
this data.
3. Use the TI-83 graphing calculator to find the quadratic regression equation for the position-time
data (STAT CALC  QuadReg). Record this equation and the correlation coefficient of the
position-time graph.
4. Draw a tangent line at t = 0.05s. Find the slope of this line (the slope will represent the
instantaneous velocity of the puck at that time).
5. Repeat step #3 for every second consecutive time (i.e. t = 0.15s, 0.25s, 0.35s…).
6. Make an instantaneous velocity-time table of your measurements.
7. Create an instantaneous velocity-time graph of your data.
8. Find the linear regression equation using the TI-83 graphing calculator. If doing exemplary work
or advanced studies, find the line of best fit and correlation coefficient by hand using the least
squares method.

Summary Questions:

1. What is the constant acceleration of the puck? (Be sure to include a direction in your answer)
2. How do you know that your line of best fit appropriately models the instantaneous velocity-time
data?
3. Create a word problem using the data and line of best fit from your experiment that interpolates a
particular velocity-time data set. Show the worked solution to this problem.
4. Create a word problem using the data and line of best fit from your experiment that extrapolates
a particular velocity-time data set. Show the worked solution to this problem.
5. Write an operational definition of constant acceleration using the air table experiment as context.
6. EXEMPLARY/ADVANCED STUDENTS ONLY: Using the article “Common Sense Concepts
Explain the acceleration of the puck down the inclined air table using Aristotelian, Impetus and
Newtonian theories.

Lab Report Submission

Students should include the following items in their lab report:
1. Title/Date(s) of lab activity
2. Purpose
3. Theory of the concept of constant acceleration. This section would include:
a. Define instantaneous velocity and acceleration.
b. Define parabola.
c. Explanation of relevant equations and statistics used.
4. Brief overview of procedure (not as outlined verbatim).
5. Data analysis. This section would include:
a. Data table of position and time.
b. Graph of position vs. time. Be sure to scale and label axes. Always include origin (0,0)
on the graph. Graph should be include a descriptive title (do not use „position vs. time
graph‟)
c. Graph of the quadratic regression equation.
d. Tangent lines and three examples of calculations for slopes of tangent lines.
e. Data table of instantaneous velocity and time.
f. Graph of instantaneous velocity and time.
g. Graph of linear regression equation.
6. Answers to the summary questions.
7. Description of sources of error (never use „human error‟ as an example; be specific)
8. Conclusion (the operational definition of constant acceleration and the actual constant
acceleration of the puck would be included here)

Due Date: ________________________________

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