group+017

=**Pre-Lab**=

For our project, we created a catapult to throw an electric rock a small distance, which would create a recoil problem. Someone is going to hold the catapult and then release the rock, causing it to fly a short distance. From there we will be able to calculate distance from where the rock left the catapult and landed on the ground surface, and also how far back the catapult rolled. Using ViVfdat and a number of other equations, we can find out the initial velocities right after the rock is released.
 * Overview**


 * Equipment**
 * catapult
 * magnetic rock
 * carbon paper
 * meter stick
 * computer paper
 * tape
 * camera

Being the fact that we have a catapult, we need to make sure that the space used is clear of any people in case of injury. Overall, we have a safe project, considering the rock won't go that far.
 * Safety Precautions**

=Procedure=

The purpose of this project is to accurately create an experiment illustrating the conservation of momentum. To accomplish this goal, we built our very own catapult to accurately simulate the total momentum being conserved in a recoil problem. In theory the total momentum should be equal before and after the catapult has been fired. The total movement of the rock after leaving the catapult replicated a bomber problem. In order to solve for velocities several trials were completed to measure the displacement of the rock, as well as finding the masses of the rock and catapult. Once the trials were complete, we measured distance the rock traveled in the ‘x’ direction as well as the displacement of the catapult when it moved backwards. The time was mathematically calculated because the Vi in the ‘y’ direction is equal to zero and acceleration in the ‘y’ direction is 9.8. In the ‘x’ direction, the acceleration is equal to zero and through more ViVfdat equations we were able to find the velocity of the rock. For the catapult, we needed to calculate Fn and µ, and Fa must be calculated using a spring scale. We calculated the Fa and weighed the catapult with the weight to find the total mass. Then, by multiplying the combined mass by Fg, we get Fn. And because Fa equals Ff, Fa divided by Fn equals µ. When calculating momentum before the rock is fired, the combined mass of the two objects is multiplied by the combined velocity, which is zero. Thus, momentum for each item is zero and total momentum is also equal to zero. After the catapult is fired the rock is separated from the catapult and each object has an individual mass. The velocities found previously will then be used to calculate the momentums, which should equal zero.

In conclusion, we found the final momentum and it turned out to be a little higher than zero, so it was not conserved. Due to the lack of high tech equipment, the friction we came up with may have be off. If we had a constant velocity, then we would have been able to get a more accurate friction. Also, due to the unevenness of the lever, the toss was not completely straight. Therefore, we might have solved an inaccurate bomber problem. Also, the weight on the catapult might have caused it to move farther away than where it started. Overall, we were pretty close to zero and we were pleased that it wasn’t.
 * Conclusion**

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