Fire Away!!!!!!!
Our experiment was to modify one variable of our trebuchet to make it shoot further. And then we take results from the other experiments to modify or trebuchet to make the best trebuchet ever.The trebuchets had to be less than a meter long at any point and consist of 2 holding arms and a firing arm.
Our trebuchet is made of various pieces of wood and some nails and a spring. We took the best results from the other teams and we modify it to give the best result. Here is the modification that we made:
When building a trebuchet, we found that the higher the spring constant and energy of the input energy, the farther the clay flew. We experimented with a weight, a rubber band, and a spring, and we find the spring being the most effective in terms of distance. We starter by building the actual trebuchet and making sure everything worked. After that we then fired the trebuchet with each energy source 5 times and recorded the data. The farthest the weight shot the projectile was around one meter, for the rubber band the farthest was 15.5 meters, and for the spring it was 20.5 meters. The spring easily had the most spring constant and it went the farthest while the weight had the lowest and went way shorter than everything. Another reason why what shot the projectile farther was the energy stored in the energy source. Since the weight was only affected by gravity it didn’t go as far. All in all we found that strong springs work best while weights won’t do much of anything.
Calculations:
Distance Horizontal= 27 meters (88.5 feet)
Time in air = 1.9 seconds
Distance Vertical = ½(a)t^2
= ½(9.8m/s)0.95s^2
=4.9(0.9025)
=4.42 meters (14.5 feet)
Velocity Vertical = d/t
= 4.42m/0.95s
= 4.65 meters per second (Almost the speed of Usain bolt.)
Velocity Horizontal = d/t
= 27m/1.9s
= 14.21 meters per second (it will be fast as a car on a regular road.)
Angle of launch = Tan^-1(4.65m/s / 14.21m/s)
Angle of launch = 18.12゜(We will get more distance than height at this angel)
Velocity total:
Cos18.21= 14.21m/s / x
0.95 = 14.21m/s /x
0.95x = 14.21m/s
x= 14.21/ 0.95
Velocity total = 14.96 meters per second (Fast as a car on a regular road.)
Spring constant:
K= 10N/0.08m
K= 125 Newtons/Meter
Spring potential Energy:
PE= ½(125n/m)(0.38m)^2
PE= ½(125n/m)(0.1444)
PE= 125(0.0722)
PE= 9.02 Joules (6.65 pound per foot)
Kinetic Energy of the Clay Ball:
KE= ½(0.007kg)(14.96m/s)^2
KE= 0.0035(244.8)
KE= 0.78 Joules (0.53 pound per foot)
Kinetic to Potential Efficiency:
E= KE/Pe
E= 0.78J/9.02J
E= 0.086
E= 8.6% (Only about a tenth of the force is transferred)
Reflection:
This project went acceptable overall. I was able to organize my team reletively well by frequetly encourging the team that we can do this. I learned that base on material limitation we need have a lot of weight to launch our projectile.
This project was an acceptable project because not everything went smoothly. Our rubber band in the begining did not do well so we have to change it to springs. I have to fight for some task within the team so we need to distrube tasks before we do them. Our trebuchet 's projectile keep getting lost, so we need to fix our arm to be more straight.
Our experiment was to modify one variable of our trebuchet to make it shoot further. And then we take results from the other experiments to modify or trebuchet to make the best trebuchet ever.The trebuchets had to be less than a meter long at any point and consist of 2 holding arms and a firing arm.
Our trebuchet is made of various pieces of wood and some nails and a spring. We took the best results from the other teams and we modify it to give the best result. Here is the modification that we made:
- We made our axle high so it will be able to free spin, and it will release our projectile higher so it will go further.
- Nail at 10° downward so the angle of release is at its most efficient point.
- No stopper is needed because the ball will release before it collide with the ground.
- We used a load to effort ratio for the launching arm of 1-1 so the weight would be balanced on either side.
- We made the piece of clay 7 grams, so it is light enough for our spring to launch it.
- We made our string at a length of 20 cm this length was long enough to extend the arch making it move faster during launch but short enough so it won’t slow down the launch.
When building a trebuchet, we found that the higher the spring constant and energy of the input energy, the farther the clay flew. We experimented with a weight, a rubber band, and a spring, and we find the spring being the most effective in terms of distance. We starter by building the actual trebuchet and making sure everything worked. After that we then fired the trebuchet with each energy source 5 times and recorded the data. The farthest the weight shot the projectile was around one meter, for the rubber band the farthest was 15.5 meters, and for the spring it was 20.5 meters. The spring easily had the most spring constant and it went the farthest while the weight had the lowest and went way shorter than everything. Another reason why what shot the projectile farther was the energy stored in the energy source. Since the weight was only affected by gravity it didn’t go as far. All in all we found that strong springs work best while weights won’t do much of anything.
Calculations:
Distance Horizontal= 27 meters (88.5 feet)
Time in air = 1.9 seconds
Distance Vertical = ½(a)t^2
= ½(9.8m/s)0.95s^2
=4.9(0.9025)
=4.42 meters (14.5 feet)
Velocity Vertical = d/t
= 4.42m/0.95s
= 4.65 meters per second (Almost the speed of Usain bolt.)
Velocity Horizontal = d/t
= 27m/1.9s
= 14.21 meters per second (it will be fast as a car on a regular road.)
Angle of launch = Tan^-1(4.65m/s / 14.21m/s)
Angle of launch = 18.12゜(We will get more distance than height at this angel)
Velocity total:
Cos18.21= 14.21m/s / x
0.95 = 14.21m/s /x
0.95x = 14.21m/s
x= 14.21/ 0.95
Velocity total = 14.96 meters per second (Fast as a car on a regular road.)
Spring constant:
K= 10N/0.08m
K= 125 Newtons/Meter
Spring potential Energy:
PE= ½(125n/m)(0.38m)^2
PE= ½(125n/m)(0.1444)
PE= 125(0.0722)
PE= 9.02 Joules (6.65 pound per foot)
Kinetic Energy of the Clay Ball:
KE= ½(0.007kg)(14.96m/s)^2
KE= 0.0035(244.8)
KE= 0.78 Joules (0.53 pound per foot)
Kinetic to Potential Efficiency:
E= KE/Pe
E= 0.78J/9.02J
E= 0.086
E= 8.6% (Only about a tenth of the force is transferred)
Reflection:
This project went acceptable overall. I was able to organize my team reletively well by frequetly encourging the team that we can do this. I learned that base on material limitation we need have a lot of weight to launch our projectile.
This project was an acceptable project because not everything went smoothly. Our rubber band in the begining did not do well so we have to change it to springs. I have to fight for some task within the team so we need to distrube tasks before we do them. Our trebuchet 's projectile keep getting lost, so we need to fix our arm to be more straight.