Slingshot+Launching


 * Names:** Colette and Tom


 * Title:** Slingshot Launching


 * Goal:** To determine which ball (golf ball, bare wiffle ball, or covered wiffle ball) will reach the greatest height when launched from a slingshot. To understand the effects that mass and air resistance have on objects launched vertically into the air.


 * Procedure:**


 * For this experiment you will need: **

1. A video recorder 2. 16 wide set popsicle sticks 3. One bottle of glue 4. One role of duct tape 5. One large rubber band 6. One standard golf ball 7. One small wiffle ball 8. One ruler or meter stick 9. One mass-reading scale


 * Making Your Slingshot: **

1. Make two stacks of popsicle sticks that are five sticks high and two stacks that are three sticks high 2. Glue each stack and let dry 3. Position the five-high stacks into a "v" shape: glue and let dry 4. Position a three-high stack on either side of your "v" for a handle: glue and let dry 5. Fasten a large rubber band around either end of your slingshot 6. Fold one piece of duct tape to pad your slingshot: use tape to fasten to the center of your rubber band


 * Experimental Procedure: **

1. Set a ruler or meter stick in your video frame for scale 2. Position the golf ball on the slingshot pad 3. Hold your slingshot on a horizontal: shoot your ball vertically into the air ( record the motion on a video recorder ) 4. Position the wiffle ball on the slingshot pad 5. Hold your slingshot on a horizontal: shoot your ball vertically into the air (record the motion on a video recorder ) 6. Cover the holes in your wiffle ball with a piece of duct tape 7. Position the tape-capped wiffle ball on the slingshot pad 8. Hold your slingshot on a horizontal: shoot your ball vertically into the air ( record the motion on a video recorder ) 9. Use a scale to find the mass of the golf ball and the wiffle ball with and without tape 10. Upload each video onto LoggerPro and map out a dot diagram on each to your collect data



Golf Ball Launch: media type="youtube" key="iocJLLbWfJo" width="425" height="350"
 * Videos:**

Wiffle Ball Launch: media type="youtube" key="A36Bv0_ue-M" width="425" height="350"

Tape-Capped Wiffle Ball Launch: media type="youtube" key="nRbXpSmnaDU" width="425" height="350"

Data:

Mass of Golf Ball: 46 g Mass of Wiffle Ball: 6 g Mass of Tape-Capped Wiffle Ball: 10 g

Maximum Height of Golf Ball: 2.8 ft Maximum Height of Wiffle Ball: 3.5 ft Maximum Height of Tape-capped Wiffle Ball: 6.2 ft

Total Time in Air for Golf Ball: 0.85 seconds Total Time in Air for Wiffle Ball: 0.95 seconds Total Time in Air for Tape-Capped Wiffle Ball: 1.2 seconds


 * Graphs:**

Golf Ball Launch:

Wiffle Ball Launch:



Tape-Capped Wiffle Ball Launch:



This experiment shows us the direct effects of both mass and air resistance on objects launched vertically in the air with equal force. First we compared the golf ball with the covered wiffle ball. Since they both had the same shape and size, we realized that mass would affect the path that each object followed the most. We initially predicted that the golf ball would rise higher, thinking its greater mass would keep it from experiencing as much air resistance. Though we think this point is valid, we were forgetting to account for the fact that we were shooting both objects up with equal force. Since F=MA and the golf ball had a significantly bigger mass (slightly more than 4 times as big), it accelerated less over the launching period and its initial velocity was therefore also less than that of the wiffle ball. The difference in initial velocity made a bigger impact on the rising height than the effects of air resistance, and the golf ball rose 2.8 feet only slightly less than half as high as the covered wiffle ball that rose 6.2 feet. This experiment allowed us to see the effect of the mass to force ratio on a vertically launched object.
 * Reflection:**

Next we examined the differences in launch path between the covered and uncovered wiffle ball. The bare wiffle ball rose 3.5 feet while the the tape-capped wiffle ball reached the greatest maximum height of 6.2 feet. Since they had very similar masses, the force of the sling shot effected both balls accelerations during the launch period and initial velocities in very similar ways. Air resistance, however, had a huge effect on the maximum height. The uncovered wiffle ball created a lot of air turbulence and therefore encountered significantly more air resistance than the covered wiffle ball. You can tell that the shape of the object is what made the difference since their masses are so similar. The surface of the original wiffle ball was covered with holes, this design allowed for a great amount of air resistance. Our tape-capped wiffle ball was much more aerodynamic; the smoother surface allowed for less air resistance. If two objects with different masses were falling at the same time without air resistance, then they would both hit the ground at the same time. This is because the force and mass balance each other out. When air resistance is present, then the objects will hit at different times. Terminal velocity occurs when an objects force of gravity and the force of air balance out. At this point the object stops accelerating, because the net force is at 0 Newtons. The object with the higher mass will hit the ground first because the object will accelerate at higher speeds. These facts are shown up in our lab experiment. The three balls had different qualities to them. The golf ball had the most mass, the non-taped wiffle golf ball had the most air resistance, and the taped wiffle golf ball had a lesser mass then the golf ball with less air resistance then the non-taped wiffle golf ball. When we launched the golf ball up into the air, the object's mass was the big factor and dropped to the ground very fast without gaining a great amount of height. The non-taped wiffle golf ball was lighter and stayed up in the air longer because of its weight and shape. It had the most air resistance out the the three which caused it to slow down upward and fall downward slowly. The last ball was the tape-caped wiffle ball. This ball's lightness and lack of air resistance caused it to reach the highest height of the three before eventually coming to the ground slowly. These three balls showed the different effects that mass and air resistance has when they were launched from a slingshot.

There were two possible errors in this lab. The first error is that during the launching, the pull-back length of our rubber band may have not been exactly the same every time. This could have resulted in uneven forces during the three launches. It is extremely difficult to emulate the same exact length and motion all three times. For the most part though, the error would not have effect the lab greatly. The second possible error is that the sides of the rubberband were not perfectly connected to our slingshot. Because they were not taped directly to the slingshot, they could have possibly slid slightly in between trials. This would have again effected the overall force of the launches. The error would not have effected the force too severely and the lab would not have been too greatly effected.

Overall, the taped wiffle golf ball would be the best choice out of the three to achieve maximum height because of its small mass and limited to air resistance.