Projectiles Force

To calculate the force acting on the trebuchet, one must know the initial velocity which launches the ball and the angle at which the ball is launched. Also, the law of conservation of energy (kinetic and potential) is involved in this calculation.

Projectiles - Write Up

http://www.youtube.com/watch?v=7xO-TCB0t70

1.       What was your original construction idea?

Our original idea is doing a small trebuchet that have enough force to launch the tennis ball. This trebuchet requires human power to launch. 

2.       What challenges did you face in construction?

Measuring the material and assembling those parts are quite exhausting as we have to make sure that everything is fit together . Our final trebuchet is bigger than our original idea, so it requires more effort. 

3.       Did you stick with your original plan?  Why or why not?

We didn't stick to original plan. We thought about how small that was, so we determined to do the big trebuchet that launched the ball further.

4.       Explain how your device works.

We attach the counterweight to the short arm. It is about 40 lbs. We also use the string as device to launch the projectile. The ball will be placed in the basket resting on the base. When we pull the string, it will release the long arm. The counterweight will fall down, launching the ball as the long arm goes up.

5.       Where and how was this device used in history?

It was used extensively in the Middle Ages by the French. Medieval Trebuchets could launch missiles hundreds of yards at, or even over, a castle, fortress or city wall.

6.       What did you learn by constructing this device?

We learn how to construct and build a device that applying physics' theory. 

7.       What principals of physics did you utilize in this device?

We use the law of gravitational potential energy to build the trebuchet. We also apply  Conservation of Energy law. 

8.       Tell about a career where this type of device could be useful.
These trebuchet can be used in the military. Those office in military might use trebuchet to throw dead bodies or destroy castles ( which I don't usually see). Physics teacher or students major in Physics can learn how to build trebuchet to understand more about the law of physics.

9.       Could this type of device be useful in getting people to space?  Why or why not?

The escape velocity is approximately 25,053 mph. This velocity is required for the device to escape the earth and go to space. It is nearly impossible to use trebuchet for this purpose. 

Projectiles - Test Fires

We didn't do well on the accuracy test. The angle of the releasing pin on the swing arm was not consistent. We must change the angle of the pin each time of the test. The accuracy distance, therefore, was affected by the pin.

Projectiles - Safety Concerns

Safety is the most important thing to be considered when building the trebuchet. Any loose parts must be tightened. The trebuchet must be stable when firing or it will cause danger. The weight attached to the short level arms must be firm. When firing, no one should be standing near the front and the end of the projectile. Everybody should be away 2m from the projectiles and wearing goggles.