Analyzing Motion of a Tossed Ball

Projectile Motion – Video Analysis

Purpose: Investigate the parameters involved with launching a basketball at an angle. Use Logger Pro movie and data analysis for investigation.

Pre-Lab Questions:
Predict and sketch graphs that demonstrate the motion of the ball toss.
Sketch: dhorizontal vs. time, dvertical vs. time, vhorizontal vs. time, vvertical vs. time, ahorizontal vs. time, and avertical vs. time

Procedure:
1. Video tape you and a partner tossing a ball at an angle back and forth in front of the wall.
2. Connect the camera to the computer and download the video. Save the video to a folder under your name.
3. Open Logger Pro from desktop.
4. The program will open up to a blank graph.
5. Select “insert” from the menu across the top of the screen.
6. Select movie and find the file where you saved the video clip.
7. On the video clip select the video analysis button. It looks like 3 dots.
8. Play movie once straight through to get an understanding of what will happen.
9. Begin the set up by setting the scale for data collection.
10. Select the ruler (button on right side of the movie frame)
11. With the mouse click and drag a line segment that matches the meter stick that is set up at the base of the wall in the middle of the movie frame.
12. Enter the value 1 meter when prompted by the program.
13. Set the origin (third button from top on right side of frame)
a. Play movie and stop when ball is just about to be shot and move the origin (click and drag) to the center of the ball.
14. Collecting data points
a. Select second button from the top on the right side of the frame
b. Mark position of ball with cross hairs and click mouse
c. The movie will advance by a frame and re-select the center of the ball to collect the next data point.

Data Collection: make sure you report the correct units and (+ or - ) with your answers!!

Velocity Initial Horizontal
Velocity Initial Vertical
Acceleration Initial Horizontal
Acceleration Initial Vertical
Displacement vertical (maximum) [height]
Displacement horizontal (maximum) [range]
Velocity Vertical at highest point
Velocity Horizontal at highest point
Acceleration Vertical at highest point
Acceleration Horizontal at highest point
Velocity Final Horizontal
Velocity Final Vertical



Analysis:

1. Do the graphs produced through the data collection on the movie match your predictions?____ If no, explain or sketch any differences that were found as a result of the activity.
If yes, explain why you successfully knew the outcome (reading activity, previous experience, etc.)

2. What is the velocity of the ball (horizontally and vertically) when it has reached maximum height? Why is the ball traveling at those values?

3. What is the acceleration of the ball (horizontally and vertically) when it has reached its maximum height? Why does it have those values?

4. If the basketball had been launched at a different angle (steeper) how would the parameters measured changed? A shallower angle?

5. If the ball tossed had been a tennis ball, how would the parameters measured change?

6. What effects would including air resistance have on the parameters of the flight of the ball?

Conclusion: Restate the purpose and discuss possible sources of error.