Conclusion Questions
1. Why did your group choose the final design of your catapult?
My partner and I decided to make the ballista catapult because it was the one we understood the most. We had a good idea about how we would go about making it and we knew how we wanted it to work. We of course had to make adjustments throughout the building process, but because we had thought about the different pieces separately and how we would eventually piece the parts together, making adjustments on individual parts was simple.
2. Explain how the catapult set the projectile in motion; from the trigger to the launch.
We had a pouch for our projectile to rest in, and a piece of string attached to the pouch. We also had a clothespin at the end of the track. All we had to do was pull the string back and clip it wherever we wanted to on the string. From there we just had to push down on the end of the clothespin, which would release the tension from the rubber bands being pulled back, thus launching the projectile from its pouch.
3. Give at least three specific examples of the forces that acted upon the projectile. Explain how and when they acted on the projectile.
Gravity, tension, and friction. Tension came into play first. As you pull back the pouch, it puts tension on the rubber bands, which is released when you press the trigger. Had there not been any tension, the projectile would not have launched at all. Next you have friction as the pouch rubs against the track. If there had not been any friction, then the projectile would have gone farther. Finally, gravity acts on the projectile. After the projectile is launched from the catapult
4. What helped the catapult work as well as it did?
There were certain aspects of the catapult that really helped it launch well. The tension in the rubber band for example. The catapult's design was also simple, which helped lower the amount of mistakes that could have been made while making the catapult.
5. Explain thoroughly how each of Newton's Three Laws affected your catapult's motion. Give specific examples.
1st Law: After the projectile launched, it had to come down because an unbalanced force (gravity) was acting upon it. Had gravity been out of the question, the projectile would have kept flying in the direction it had been going on because an object in motion will stay in motion unless acted upon by an unbalanced force.
2nd Law: When experimenting with the catapult, we had to experiment with different sized projectiles to figure out which one works the best for launching. This is because of Newton's second law F=ma. Had we used a larger projectile with more mass, then we would have needed more force to make it go the same distance. If we had used a smaller projectile with less mass, then we would have needed less force to get the projectile to go 3 meters.
3rd Law: As the string is pulled back and placed in the clothespin, there is an equal and opposite reaction going on. The clothespin has the equal and opposite reaction while holding onto the string so as not to let it go. They are both pushing on each other with the same force and as a result, neither the string nor the clothespin moves.
6. Explain the impact friction had on your project, including the type of friction.
There are two accounts in which friction has affected the project. One is when the projectile is actually being launched. The pouch has to slide across the rail, which causes friction, which will in turn slow down the pouch. The next account of friction affecting the project is when the projectile is in the air. This is called air resistance and is when the air slows down the projectile so that it doesn't go as far as it would if the friction and air resistance wasn't there. Of course, in both cases, the actual effect is has on the projectile and pouch is miniscule and unnoticeable.
7. Identify the types of energy that exist and list all the energy transformations that occur.
onto the There are two different types of energy. That is potential energy, which is the energy you possess but aren't currently using. With the catapult, that is the energy found when the string is pulled back and fastened in the clothespin. The energy is in the rubber band, but it isn't being put to use yet. The next type of energy is kinetic energy. This is the energy you have when you are moving. As far as the catapult goes, the projectile has kinetic energy when it is being launched and when it is actually in flight.
8. What are at least three things that you could have done to make the catapult better? In other words, what are at least three things that could have made your catapult launch the catapult to land closer to the target?
1. We could have replaced the string with another rubber band so that it didn't move so much when it was placed in the clothespin.
2. Made the pouch out of a different material.
3. Made a more sophisticated trigger mechanism.
4. Have an actual engineer make it. (Thanks Morticia!)
9. What other experiments might you want to do with your catapult?
Test out how far the projectile goes when you put the clothespin on different parts of the string and actually make the string. See how far the catapult can actually launch.
My partner and I decided to make the ballista catapult because it was the one we understood the most. We had a good idea about how we would go about making it and we knew how we wanted it to work. We of course had to make adjustments throughout the building process, but because we had thought about the different pieces separately and how we would eventually piece the parts together, making adjustments on individual parts was simple.
2. Explain how the catapult set the projectile in motion; from the trigger to the launch.
We had a pouch for our projectile to rest in, and a piece of string attached to the pouch. We also had a clothespin at the end of the track. All we had to do was pull the string back and clip it wherever we wanted to on the string. From there we just had to push down on the end of the clothespin, which would release the tension from the rubber bands being pulled back, thus launching the projectile from its pouch.
3. Give at least three specific examples of the forces that acted upon the projectile. Explain how and when they acted on the projectile.
Gravity, tension, and friction. Tension came into play first. As you pull back the pouch, it puts tension on the rubber bands, which is released when you press the trigger. Had there not been any tension, the projectile would not have launched at all. Next you have friction as the pouch rubs against the track. If there had not been any friction, then the projectile would have gone farther. Finally, gravity acts on the projectile. After the projectile is launched from the catapult
4. What helped the catapult work as well as it did?
There were certain aspects of the catapult that really helped it launch well. The tension in the rubber band for example. The catapult's design was also simple, which helped lower the amount of mistakes that could have been made while making the catapult.
5. Explain thoroughly how each of Newton's Three Laws affected your catapult's motion. Give specific examples.
1st Law: After the projectile launched, it had to come down because an unbalanced force (gravity) was acting upon it. Had gravity been out of the question, the projectile would have kept flying in the direction it had been going on because an object in motion will stay in motion unless acted upon by an unbalanced force.
2nd Law: When experimenting with the catapult, we had to experiment with different sized projectiles to figure out which one works the best for launching. This is because of Newton's second law F=ma. Had we used a larger projectile with more mass, then we would have needed more force to make it go the same distance. If we had used a smaller projectile with less mass, then we would have needed less force to get the projectile to go 3 meters.
3rd Law: As the string is pulled back and placed in the clothespin, there is an equal and opposite reaction going on. The clothespin has the equal and opposite reaction while holding onto the string so as not to let it go. They are both pushing on each other with the same force and as a result, neither the string nor the clothespin moves.
6. Explain the impact friction had on your project, including the type of friction.
There are two accounts in which friction has affected the project. One is when the projectile is actually being launched. The pouch has to slide across the rail, which causes friction, which will in turn slow down the pouch. The next account of friction affecting the project is when the projectile is in the air. This is called air resistance and is when the air slows down the projectile so that it doesn't go as far as it would if the friction and air resistance wasn't there. Of course, in both cases, the actual effect is has on the projectile and pouch is miniscule and unnoticeable.
7. Identify the types of energy that exist and list all the energy transformations that occur.
onto the There are two different types of energy. That is potential energy, which is the energy you possess but aren't currently using. With the catapult, that is the energy found when the string is pulled back and fastened in the clothespin. The energy is in the rubber band, but it isn't being put to use yet. The next type of energy is kinetic energy. This is the energy you have when you are moving. As far as the catapult goes, the projectile has kinetic energy when it is being launched and when it is actually in flight.
8. What are at least three things that you could have done to make the catapult better? In other words, what are at least three things that could have made your catapult launch the catapult to land closer to the target?
1. We could have replaced the string with another rubber band so that it didn't move so much when it was placed in the clothespin.
2. Made the pouch out of a different material.
3. Made a more sophisticated trigger mechanism.
4. Have an actual engineer make it. (Thanks Morticia!)
9. What other experiments might you want to do with your catapult?
Test out how far the projectile goes when you put the clothespin on different parts of the string and actually make the string. See how far the catapult can actually launch.