Vernier Software and Technology
Vernier Software & Technology

2D Vectors: Pool Ball Displacement, Velocity, and Speed


A careful analysis of two-dimensional motion is more complex than it is for motion in one dimension – especially when calculating velocities and speeds. In this activity you are going to analyze a movie that shows the 2D motion of a pool ball rolling on a level pool table. The ball starts with its center at point A, moves “up” and to the left to point B, bounces off the edge of the table and rolls “down” and to the left so that its center reaches point C.


In this activity, you will

  • Scale a movie.
  • Use displacement vectors to find average speed and average velocity.
  • Show that the magnitude of the average velocity, \left| {\left\langle {{{\vec v}_{{\text{A}} \to {\text{C}}}}} \right\rangle } \right|, of object moving in 2D is not always the same as its average speed, \left\langle {{S_{{\text{A}} \to {\text{C}}}}} \right\rangle .

Software for Experiment

This experiment uses Logger Pro software for video analysis. The video for analysis is included with the lab book.

Physics with Video Analysis

See other experiments from the lab book.

1Rolling Ball
2Big and Small: How to Scale an Image
3Velocity Change
4Velocity and Speed
5Velocity and Acceleration
6Three Movies: Determining Constant Acceleration
7Demon Drop: A Mathematical Modeling Activity
8Jumping on the Moon
92D Vectors: Pool Ball Displacement, Velocity, and Speed
10Galileo's Projectile I: Using 17th Century Techniques
11Galileo's Projectile II: Using Contemporary Techniques
12Projectile Motion Vectors
13Frictional Slowing
14Impulsive Juggling
15Center of Mass Motions
16Finding a Spring Constant
17Net Work - Kinetic Energy Theorem
19Slinky Wave Speeds
20Superposition of Slinky Waves
21A Wave Pulse Equation
22Doppler Effect: Surface Water Waves
23Doppler Effect: Sound Waves
24A Heat Engine: Relating Work to the P-V Cycle
25Coulomb's Law for Two Charged Spheres
26Discharge Rate
27Electric Field Due to a Line of Charge
28Resistance and Ohm's Law
29Parallel Plate Capacitor: Potential Difference vs. Spacing
30Wiring Capacitors in Series and Parallel
31Using RC Decay to Determine Capacitance
32Exploring Faraday's Law
33Snell's Law of Refraction

Experiment 9 from Physics with Video Analysis Lab Book

<em>Physics with Video Analysis</em> book cover

Included in the Lab Book

Vernier lab books include word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.

Buy the Book

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