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The Conservation of Momentum: In an inelastic experiment 

What we did:  Our experiment was testing for conversation of momentum in an inelastic collision. The two objects colliding in our experiment were a small, foam dart and a plastic cup. The small foam dart was shot into the cup at a close distance. The cup and dart were lined with tape in order to create the inelastic collision. The cup was at the edge of a table, so when the two collide, the cup fell and a bomber problem was created. It fell onto a piece of paper will carbon paper under it so we could find the horizontal distance it fell over. We used the data from the bomber problem to find the velocities and the masses we measured in order to discover the momentum of this system before and after the collision. Link to video: http://www.facebook.com/video/?id=541085504#/video/video.php?v=72644860504 media type="custom" key="2969490"

Procedure: 1. Place a black piece of paper with carbon paper over it on the ground near the edge of the table. 2. Add tape to the bottom of the cup and to the tip of the nerf 3. Measure the mass of the nerf with tape added 4. Mass the cup with tape added 5. Place the cup on its side and put it on the end of the table so the bottom of the cup is 2 cm off of the edge of the table 6. Place the nerf inside the nerf gun 7. Place the nerf a cm away from the mouth of the cup. Hold the nerf gun horizontally and make sure the nerf gun is almost touching the table 8. Shoot the nerf into the cup, causing the cup and nerf to fall together onto the ground 9. Repeat steps 1-6 two more times 10. Measure the delta x from the bottom of the table (on the ground) to the marks on the carbon paper 11. Place the nerf gun at the same height it was in step 5 12. Shoot the nerf 13. Mark where the nerf landed with masking tape 14. Repeat steps 8-10 two more times <span style="font-family: Tahoma,Geneva,sans-serif;">15. Measure the delta x from the bottom of the table (on the ground) to each tape mark <span style="font-family: Tahoma,Geneva,sans-serif;">16. Using the mass from step 1 and the Vi found from using the averages of the delta x from step 12, find the momentum of just the nerf <span style="font-family: Tahoma,Geneva,sans-serif;">17. Add the mass of the cup and nerf <span style="font-family: Tahoma,Geneva,sans-serif;">18. Solve for the velocity using ViVfDAT with the distance being the average distances measured in step 8 <span style="font-family: Tahoma,Geneva,sans-serif;">19. Use the sum of the two masses multiplied by the velocity solved for in step 15 to find the momentum of the cup and nerf. <span style="font-family: Tahoma,Geneva,sans-serif;">20. Compare the momentum of the nerf from step 15 and the momentum of the cup and nerf from step 18 to see if answers are the same or almost the same. If so, momentum was conserved

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Conclusion: <span style="font-family: Tahoma,Geneva,sans-serif;">Our momentum project was an inelastic collision that effectively conserved momentum. The percent error, calculated by subtracting the smaller momentum from the larger and dividing by their average, was 9.2 percent. This means the difference in momentums from before and after the collision was less than a 10 percent difference. Momentum was conserved because there were no outside forces acting on our collision. Because it was a bomber problem, there was no movement between surfaces to cause friction. These velocities were able to remain constant due to this lack of outside forces (except for possible air resistance, which was minimal enough to not create an obvious loss of conservation). The 1.93 m/s velocity of the dart and the .53 m/s velocity experienced were constant, experiencing no deceleration, the main factor in conservation. As well, the masses remained constant throughout the collision, contributing to constant momentums. Although conversation of momentum should be present, there were still errors to negatively affect the data. For example, the dart only had two wings on it; this could have caused a slightly errant flight pattern. If the arrow did not consistently hit the cup directly at the center of its bottom, the fall could have take place on a small angle, affecting its delta X distance and our data. A wrong delta X would eventually give a less accurate velocity and momentum. The nerf could have experienced bending during the trials, causing the same loss of accuracy in results as the loss of the wings did. As well, the shaky hand of a shooter could cause a slight change in trajectory, causing the same type of results just previously described. As well, the addition of tape to the bottom of the cup and nerf could have caused a change in impulse. Because the tape would increase time, the force would decrease, and therefore acceleration would decrease. This lessening in acceleration would affect the change in velocity, and our new momentum.



Prelab: Our experiment will be the test for conversation of momentum in a inelastic collision. The two objects colliding in our experiment will be a small foam dart and a plastic cup. The small foam dart will be shot into the cup at a close distance. The cup and dart will be lined with tape in order to create the inelastic collision. The cup will be at the edge of a table, so when the two collide, the cup falls and a bomber problem is created. It will fall onto a piece of paper will carbon paper under it so we can find the horizontal distance it fell over. As well, we will use a food scale to figure out the masses of the objects used the in experiment. Safety precautions will to make sure no person points the dart gun at their eyes, although errant darts are not really an issue because of the proximity of the shooter and the cup, and the darts low velocity. We will use the data from the bomber problem created in order to discover the momentum of this system before and after the collision.