Wednesday, December 22, 2010

Marshmallow Catapults

Trebuchet Project
Benchmark on Projectile and Rotary Motion

Build a trebuchet that is capable of launching a large marshmallow from a distance of 3 to 5 meters, and hitting a target that is .30 m high +/- .10 m. You will have 5 trials to hit your target, and will be graded according to your building design, accuracy, and analysis.


Questions for Analysis
(To be completed individually)

  1. Where is the biggest frictional issue in your machine?  Explain why this matters to the momentum of the mallow.
  2. Determine the maximum range for your trebuchet, t(calc), and the initial values of v(x) and v(y) including a diagram  using logger pro
  3. How could you determine F(net) of the mallow?
  4. How will the momentum of the projectile change if we use jawbreakers instead of marshmallows?  An orange?  Why?
  5. Pick a time frame for your catapult.   Determine the change in t, the acceleration due to gravity, and the distance traveled.  Based on this, calculate v(i) at the beginning of the interval and v(f) at the end of the interval in the x and the y directions.   Choose your interval carefully so you are not mixing y(up) and y(down)
  6. Write a three to five paragraph summary of how you would change the design if you built another machine, and what you have learned about physics.  Include the following terms:  potential energy, kinetic energy, frictional force, net force, acceleration of gravity, vector errors, kinematic equations, independent x and y motions.

1 comment:

  1. 1. The biggest frictional issue in our machine would be the spring on our mouse trap. This is an issue because if the spring is not wound tight then there isn’t as much force to the marshmallow and it doesn’t shoot as far as if the spring were wound tight.
    2.
    3. We can determine F(net) by calculating the mass of the marshmallow and finding the acceleration of the marshmallow when it is ejected into the air.
    4. The momentum will increase from a marshmallow to a jawbreaker because the weight of a jawbreaker is lighter then a marshmallow so it will pick up more speed. If we used an orange the momentum will decrease because the weight of an orange is a lot heavier then a marshmallow and the weight will slow it down and won’t go as far.
    5.
    6. If I were to build another mouse trap catapult, I would use a longer spoon because it will give me a longer throw and the projectile will go farther. The longer spoon increases its potential energy and net force as well as gives me a greater adjustment to correct vector errors by bending the angle of the spoon. If I could reduce the frictional force on the mouse trap spring, I could increase its ability to release its energy at a faster rate. The weight of the marshmallow will have an impact on its potential energy and kinetic energy and will affect the distance it travels. If it is too light or too heavy it will not travel as far. Although the acceleration of gravity can not be changed, by increasing the y motion, which is its height, the x motion should also increase as the arc provides greater distance. Evaluating forces and energy along with x y motions should be resolved using kinematic equations to prove theories.
    -Rylie Worm and Rachel Heveron

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