Air Resistance of Tennis Ball

Group Members: Ty Giacalone, Erin Gray, Yujin Lee

Goal:To determine the air resistance of a naked tennis ball versus a new tennis ball at various speeds.

Procedure:1. Build apparatus as shown in diagram.2. Attach new tennis ball to apparatus.3. Hold apparatus outside sunroof, making sure it is level.4. Accelerate to 45 mph and then record reading from spring scale.5. Repeat at 55 mph and 65 mph and record data.6. Next replace new tennis ball with naked tennis ball and run experiment at 45

mph, 55 mph, and 65 mph and record data.

Observations:First attempt: Our first attempt involved a shorter wind tunnel than our successful attempt. The ball experienced much turbulence and the spring scale readings were unreadable due to the oscillation of the scale.

Spring Scale

Wind Tunnel

Pulley

Railings

Tennis Ball

Second attempt: We extended the wind tunnel and added railings to keep the ball from moving back and forth, which thus decreased the oscillation of the spring scale, which allowed us to read the spring scale more accurately.Also, we realized that the direction we were driving had an effect on the air resistance therefore we made sure that we drove the same direction for each trial. Furthermore, we conducted the experiment within a short timeframe in order to ensure that the winds did not shift directions too drastically.

Data:New Ball

Trial 1 2 345 mph 0.3N 0.2N 0.27N55 mph 0.45N 0.35N 0.45N65 mph 0.6N 0.6N 0.6N

Naked BallTrial 1 2 3

45 mph 0.2N - 0.1N55 mph 0.25N 0.25N 0.27N65 mph 0.35N 0.35N 0.4N

Conclusion:From our data, we can deduce that the new ball has both a more consistent air resistance, as well as a higher air resistance. We believe that the uniform fuzz on the ball produced a more consistent result than the uneven patches of fuzz and rubber that remained on the naked ball. Also, the fuzz on the ball provides an increased surface area and therefore increases the ball’s air resistance. We also concluded that the direction of the wind and the direction that we drove had an effect on the recorded air resistance as well.