My experience with the trebuchet challenge project was very positive! I thoroughly enjoyed the experience. Specific things that went well for my team and myself were:
1. Teamwork: My team members are good friends of mine. This made it easy to work with other group members. This also enabled us to be very comfortable to share ideas and opinions about our trebuchet and the experience. Also, we were easily available to work together on the trebuchet in order to complete it.
2. Test Day: Test day went very well for my team. This really encouraged us and gave us motivation as we moved from test day to competition day.
3. Distance Competition: Our distance competition was very successful! We were able to achieve hurls of over 50.0 m every time with our trebuchet. We were thrilled with these results!
4. Paper Trebuchet Construction: Our paper trebuchet was constructed very quickly. This was mainly due to the fact that all of the members in my group had spares at the same time and were able to all contribute to the construction of the mini paper trebuchet.
One of the recommendations that I have for future physics 40S students for the trebuchet challenge would be to research trebuchets. Look in to how successful trebuchets have been constructed and engineered! Also, I would recommend trying a variety of pouches for the trebuchet itself. The pouch is such a crucial aspect of the trebuchet that getting the perfect pouch may make or break your entire trebuchet. A final recommendation that I have for future physics students is to not change things that work well- especially the day before, or during competition day. If you have your trebuchet hurling over 25m consistently, leave it! Don't change everything to try to drastically increase your distance because it may cause your trebuchet to have less than optimal results.
Wednesday, May 25, 2011
Trebuchet Challenge Competition Reflection
Our trebuchet performed very well in the accuracy part of the challenge! Our best hurl of the tennis ball landed 0.620 m from the center of the hula hoop- we were thrilled with these results! As a result of our success, we were awarded 2nd place in the accuracy competition and received 9/10 points!
If I had the opportunity to modify our current trebuchet, I would make it better suited for the accuracy competition. Although our bungee cords worked well in the accuracy competition, I feel that adjusting the counterweight mass may have been a better and more precise way to control the distance the tennis ball flew. The bungee cords reduced the speed at which the arm fell, reducing the velocity with which the ball was released. I feel that if we had adjusted the weight, we would have been able to more accurately adjust the range (through using different masses of weights) that our tennis ball flew.
I feel that our overall design of the trebuchet was quite excellent. If we were to create a completely new trebuchet, I think we may have used a slightly larger counterweight, which would have hopefully caused the tennis ball to fly further, improving our distance competition results.
Toward the end of the distance competition, the sewing on our pouch became loose. I feel that if we had reinforced the sewing on the pouch that the trebuchet may have performed better. Also, we could have tweaked the angle of release slightly by adjusting our nail. We did not adjust the nail however, because we felt that we had a good angle of release and chose not to alter something that had worked consistently well for us.
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| Our loaded trebuchet for the accuracy competition- ready to fire! |
If I had the opportunity to modify our current trebuchet, I would make it better suited for the accuracy competition. Although our bungee cords worked well in the accuracy competition, I feel that adjusting the counterweight mass may have been a better and more precise way to control the distance the tennis ball flew. The bungee cords reduced the speed at which the arm fell, reducing the velocity with which the ball was released. I feel that if we had adjusted the weight, we would have been able to more accurately adjust the range (through using different masses of weights) that our tennis ball flew.
I feel that our overall design of the trebuchet was quite excellent. If we were to create a completely new trebuchet, I think we may have used a slightly larger counterweight, which would have hopefully caused the tennis ball to fly further, improving our distance competition results.
Toward the end of the distance competition, the sewing on our pouch became loose. I feel that if we had reinforced the sewing on the pouch that the trebuchet may have performed better. Also, we could have tweaked the angle of release slightly by adjusting our nail. We did not adjust the nail however, because we felt that we had a good angle of release and chose not to alter something that had worked consistently well for us.
Friday, May 20, 2011
Competition Day Reflection
Our trebuchet had great results in the distance part of the competition. Our trebuchet had the greatest distance results! It had an average distance of 51.22 m. Our greatest distance achieved was 52.11 m.! We were very pleased with the results.
To make our trebuchet meet the challenges posed by the accuracy component of the competition we are going to shorten our trebuchet throwing arm and add bungee cords to the design. The bungee cords with slow down the fall of the counterweight, which will shorten the distance thrown. We are also going to reinforce the pouch to make it more durable for further trials.
To make our trebuchet meet the challenges posed by the accuracy component of the competition we are going to shorten our trebuchet throwing arm and add bungee cords to the design. The bungee cords with slow down the fall of the counterweight, which will shorten the distance thrown. We are also going to reinforce the pouch to make it more durable for further trials.
Theoretical Range and Competition Day
Range = 2 x h x (M/m)
Range = 2 x 33 cm x (22.6796 kg / 0.057 kg)
Range = 26260.59 cm
Range = 262.6 m
Average distance= (51.69m + 50.99m + 42.11m + 50.29m + 51.00m) / 5
Average distance= 51.22 m
Difference between Range and Average distance= 262.6m - 51.22m
Difference between Range and Average distance= 211.38m
Five reasons that kept us from achieving the performance suggested by the theoretical range:
1. Release Angle: The release angle of our trebuchet although close to 45 degrees, was not precisely 45 degrees. As a result our distance was not totally optimized by the design of our trebuchet.
2. Air resistance: Air resistance is completely ignored within the theoretical range of the trebuchet. Air resistance however had enormous effects on the flight of our tennis ball.Air resistance opposed the motion of the ball while in flight.
3. Release Mechanism Issues: Our pouch and release mechanism was not perfected. As a result the theoretical range of the trebuchet was not realized due to issues with release point and mechanism. The pouch was not perfected. There were issues with the ball being release at exactly the right point in time.
4. Friction: There was friction that existed between the mechanical parts of the trebuchet. These values were ignored in the calculations of the range. The friction would have hindered the results of the trebuchet.
5. Air resistance of the tennis ball: A tennis ball was not the ideal object to be thrown by a trebuchet. The textured edges of the tennis ball created excess air resistance between the tennis ball fuzz and the air.
Range = 2 x 33 cm x (22.6796 kg / 0.057 kg)
Range = 26260.59 cm
Range = 262.6 m
Average distance= (51.69m + 50.99m + 42.11m + 50.29m + 51.00m) / 5
Average distance= 51.22 m
Difference between Range and Average distance= 262.6m - 51.22m
Difference between Range and Average distance= 211.38m
Five reasons that kept us from achieving the performance suggested by the theoretical range:
1. Release Angle: The release angle of our trebuchet although close to 45 degrees, was not precisely 45 degrees. As a result our distance was not totally optimized by the design of our trebuchet.
2. Air resistance: Air resistance is completely ignored within the theoretical range of the trebuchet. Air resistance however had enormous effects on the flight of our tennis ball.Air resistance opposed the motion of the ball while in flight.
3. Release Mechanism Issues: Our pouch and release mechanism was not perfected. As a result the theoretical range of the trebuchet was not realized due to issues with release point and mechanism. The pouch was not perfected. There were issues with the ball being release at exactly the right point in time.
4. Friction: There was friction that existed between the mechanical parts of the trebuchet. These values were ignored in the calculations of the range. The friction would have hindered the results of the trebuchet.
5. Air resistance of the tennis ball: A tennis ball was not the ideal object to be thrown by a trebuchet. The textured edges of the tennis ball created excess air resistance between the tennis ball fuzz and the air.
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| Our trebuchet loaded and ready to go for the distance competition on competition day! |
Wednesday, May 18, 2011
Trebuchet Challenge Test Day
Our trebuchet challenge test day was very successful! Our trebuchet had many successful trials. Our best trial achieved a distance of 60 m! We were very pleased. A probable factor that aided our success was having a strong wind at our backs which helped our tennis ball fly very far. Hopefully we have the wind on our side on challenge day!
On test day, we had not made adjustments to alter our trebuchet for the accuracy competition. However, thoughout the week we worked on our trebuchet and came up with a system that reduced the distance that the trebuchet hurled the ball by decreasing the speed and the distance with which the counterweight fell.
Throughout the process of making our trebuchet, we had to remake a pouch. Our pouch design, though simple, works very well. It is made of lightweight cotton, and ribbon. Hopefully it is durable enough to last for test day!
Below is a video of our trebuchet in action!
On test day, we had not made adjustments to alter our trebuchet for the accuracy competition. However, thoughout the week we worked on our trebuchet and came up with a system that reduced the distance that the trebuchet hurled the ball by decreasing the speed and the distance with which the counterweight fell.
Throughout the process of making our trebuchet, we had to remake a pouch. Our pouch design, though simple, works very well. It is made of lightweight cotton, and ribbon. Hopefully it is durable enough to last for test day!
Below is a video of our trebuchet in action!
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| Our trebuchet on test day! |
Wednesday, May 4, 2011
Trebuchet Challenge Project Post #1
Creating our paper trebuchet was fun and a true learning experience! We created our trebuchet, at it successfully achieved both the distance and accuracy requirements.
Creating the paper trebuchet was relatively easy. There was some slight frustration with the cutting and folding at the start. It was somewhat difficult to know which lines to cut, which lines to fold up, and which lines to fold down. It was also relatively difficult to create an appropriate pouch. It was difficult to create a pouch that held the ball tight enough so that it would not fall out, but not too tight as to prevent the ball from being released.
Air resistance was relatively minimal in operating our paper trebuchet. Air resistance was hard to recognize and did not have a recognizable effect on the flight of our ball. We can, however, know that there was air resistance present.
Gravity played a huge role in our operating our trebuchet. We had to work with gravity to create a trebuchet that released the ball at a point that would created optimal results in both distance and accuracy.
The angle of release on our trebuchet was 45 degrees. This truly optimized the distance our trebuchet hurled the ball. When the angle of release is 45 degrees, a specific relationship exists between the x and y components that shows optimal results in hurling distance.
The counterweight we used for the distance competition was very large. We used approximately 40 individual weights to optimize our distance. When we were concerned with accuracy, we decreased the number of weights weights to 25 weight, which reduced the distance that the ball would go, without compromising the angle of release.
Creating the paper trebuchet was relatively easy. There was some slight frustration with the cutting and folding at the start. It was somewhat difficult to know which lines to cut, which lines to fold up, and which lines to fold down. It was also relatively difficult to create an appropriate pouch. It was difficult to create a pouch that held the ball tight enough so that it would not fall out, but not too tight as to prevent the ball from being released.
Air resistance was relatively minimal in operating our paper trebuchet. Air resistance was hard to recognize and did not have a recognizable effect on the flight of our ball. We can, however, know that there was air resistance present.
Gravity played a huge role in our operating our trebuchet. We had to work with gravity to create a trebuchet that released the ball at a point that would created optimal results in both distance and accuracy.
The angle of release on our trebuchet was 45 degrees. This truly optimized the distance our trebuchet hurled the ball. When the angle of release is 45 degrees, a specific relationship exists between the x and y components that shows optimal results in hurling distance.
The counterweight we used for the distance competition was very large. We used approximately 40 individual weights to optimize our distance. When we were concerned with accuracy, we decreased the number of weights weights to 25 weight, which reduced the distance that the ball would go, without compromising the angle of release.
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| The trebuchet and myself! |
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