Analyzing the motion of a Tossed Ball.

1. Set-up the LabPro for data collection and connect a motion sensor to Dig/Sonic 2. Open the file Kinematics_of_Ball.xmbl. Zero the sensor (Cntrl-0). The experiment file is set up so that motion away from the detector (down) is negative.

If you wish to save the data, the best method is to save the file to My Documents and send it to yourself, either by ftp (you computer jocks can handle this) or by attaching a file to an e-mail using Internet explorer and pointing to webmail.rit.edu.

You may download a demo version of the software (it does everything except connect to the sensors) at:
http://www.vernier.com/downloads/index.html. Note: there is a link on the lab page of the class website.

2. Clamp a rod to the table, a second rod at the top and the motion sensor pointing down. On the attached graphs, sketch your predictions for the graphs of position, velocity, and acceleration for a ball tossed upwards toward the sensor. Sketch these on the 3 left hand graphs on the next page. Include the time before you toss the object and after you catch it.

Then collect data. You may need to adjust the position and aim of the sensor in order to get a good result.

3. Make sketches of what you actually measure on the 3 right hand graphs on the next page. Identify (and label) the portions of the sketches when the ball is in your hand, and when it out of your hand.

Analysis

1. Select a region of the position graph when the ball is not in your hand. Choose Automatic Curve Fit (under the Analyze menu or the "f(x)" icon) and do a quadratic fit. Record the coefficients and attach the proper units to them. What is the name for each coefficient, i.e. things like initial position, x₀.

2. Click on the velocity-time graph. Drag across the same region as above and do a Linear Fit (Analysis menu or the "R =" icon). Record the coefficients and attach units to them and the name of each.

3. Click in the acceleration-time graph. Drag across the same region and determine the average by using Statistics (Analysis menu or the "Stat" button). Record the average value, tell the name of this quantity and its units. Also record the standard deviation.

4. Do your results of the three previous parts agree? For example, do they all give the same value of initial velocity, etc.

What to submit:   one per group, due today or Wed/Fri, it can be handwritten.
• [5 points] Your predicted and observed graphs;
• [10 points] Answers to "Analysis" questions 1-3;
• [5 points] Rewrite of your quadratic fit equation with the correct symbols substituted for the variables and including the units for each constant;
• [10 points] Paragraph discussing how your obsevations did or did not agree with your predictions [Analysis 4].

Prediction graphs	Observed Graphs

This page maintained by Anne G. Young. Last modified 12-Dec-2003 .