Evan,+Erica,+Aaron

= = = = = Ballistic Pendulum Lab = __Honors Physics Period 2__ __4/4/11__


 * PROBLEM**


 * PURPOSE**


 * HYPOTHESIS**


 * MATERIALS**


 * PROCEDURE**

**DATA**



**CALCULATIONS**

==






 * DISCUSSION QUESTIONS**

 1. In general, what kind of collision conserves kinetic energy? What kind doesn’t? What kind results in maximum loss of kinetic energy?   2. Consider the collision between the ball and pendulum.  a. Is it elastic or inelastic?  b. Is energy conserved?  c. Is momentum conserved?   3. Consider the swing and rise of the pendulum and embedded ball.  a. Is energy conserved from the moment just before the ball strikes the pendulum to the moment the pendulum rises to its maximum height?  b. How about momentum?   4. It would greatly simplify the calculations if kinetic energy were conserved in the collision between ball and pendulum.  a. Calculate the loss in kinetic energy as the difference between the kinetic energy before and immediately after the collision between ball and pendulum.  b. What is the percentage loss in kinetic energy? Find by dividing the loss by the original kinetic energy. <span style="margin-left: 1.25in; mso-layout-grid-align: none; mso-list: l0 level3 lfo1; mso-pagination: none; tab-stops: 27.0pt 84.0pt list 1.25in left 112.0pt 140.0pt 168.0pt 196.0pt 224.0pt 3.5in 280.0pt 308.0pt 336.0pt; text-autospace: none; text-indent: -.25in;"> c. According to your calculations, would it be valid to assume that energy was conserved in that collision? <span style="margin-left: 1.25in; mso-layout-grid-align: none; mso-list: l0 level3 lfo1; mso-pagination: none; tab-stops: 27.0pt 84.0pt list 1.25in left 112.0pt 140.0pt 168.0pt 196.0pt 224.0pt 3.5in 280.0pt 308.0pt 336.0pt; text-autospace: none; text-indent: -.25in;"> d. Calculate the ratio M/(m+M). Compare this ratio with the ratio calculated in part (b). Theoretically, these two ratios should be the same. State the level of agreement for these two quantities for your data. <span style="margin-left: 1.0in; mso-layout-grid-align: none; mso-pagination: none; tab-stops: 27.0pt 84.0pt 112.0pt 140.0pt 168.0pt 196.0pt 224.0pt 3.5in 280.0pt 308.0pt 336.0pt; text-autospace: none;"> <span style="margin-left: 27.0pt; mso-layout-grid-align: none; mso-list: l0 level2 lfo1; mso-pagination: none; tab-stops: 27.0pt 84.0pt 112.0pt 140.0pt 168.0pt 196.0pt 224.0pt 3.5in 280.0pt 308.0pt 336.0pt; text-autospace: none; text-indent: -27.0pt;"> 5. Go to []. Select “Ballistic Pendulum” from the column on the left. What is the effect of increasing the mass of the ball? What is the effect of increasing the pendulum mass? Try it. (NOTE: You have to read “Student Notes” first before you can run the simulation.) <span style="mso-layout-grid-align: none; mso-pagination: none; tab-stops: 27.0pt 84.0pt 112.0pt 140.0pt 168.0pt 196.0pt 224.0pt 3.5in 280.0pt 308.0pt 336.0pt; text-autospace: none;"> <span style="margin-left: 27.0pt; mso-layout-grid-align: none; mso-list: l0 level2 lfo1; mso-pagination: none; tab-stops: 27.0pt 84.0pt 112.0pt 140.0pt 168.0pt 196.0pt 224.0pt 3.5in 280.0pt 308.0pt 336.0pt; text-autospace: none; text-indent: -27.0pt;"> 6. Is there a significant difference between the two calculated values of velocity? What factors would increase the difference between these two results? How would you build a ballistic pendulum so that momentum method gave better results?

= = =<span style="font-size: 1.4em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;">** 2-D Collisions with Hover Pucks ** =
 * CONCLUSION**

__Honors Physics Period 2__ __3/30/11__


 * PROBLEM**

To show that the momentum is conserved in two dimensions for elastic and inelastic collisions.
 * PURPOSE**


 * HYPOTHESIS**

2 hover pucks, launcher, plumb bomb, measuring tape, protractor, sandbags, stopwatches
 * MATERIALS**

1. 2.
 * PROCEDURE**


 * DATA**


 * DIAGRAM**






 * CALCULATIONS**


 * DISCUSSION QUESTIONS**
 * <span style="font-family: Arial,Helvetica,sans-serif;">1. In general, what kind of collision conserves kinetic energy? What kind doesn’t? What kind results in maximum loss of kinetic energy? **


 * <span style="font-family: Arial,Helvetica,sans-serif;">2. Consider the collision between the two hoverpucks. **
 * <span style="font-family: Arial,Helvetica,sans-serif;">a. Is it elastic or inelastic? **
 * <span style="font-family: Arial,Helvetica,sans-serif;">b. Is energy conserved? **
 * <span style="font-family: Arial,Helvetica,sans-serif;">c. Is momentum conserved? **


 * <span style="font-family: Arial,Helvetica,sans-serif;">3. It would greatly simplify the calculations if kinetic energy were conserved in the collision between two hover pucks. **
 * <span style="font-family: Arial,Helvetica,sans-serif;">a. Calculate the loss in kinetic energy as the difference between the kinetic energy before and immediately after the collision. **
 * <span style="font-family: Arial,Helvetica,sans-serif;">b. What is the percentage loss in kinetic energy? Find by dividing the loss by the original kinetic energy. **
 * <span style="font-family: Arial,Helvetica,sans-serif;">c. According to your calculations, would it be valid to assume that energy was conserved in that collision? **
 * <span style="font-family: Arial,Helvetica,sans-serif;">d. Calculate the ratio M/(m+M). Compare this ratio with the ratio calculated in part (b). Theoretically, these two ratios should be the same. State the level of agreement for these two quantities for your data. **


 * <span style="font-family: Arial,Helvetica,sans-serif;">4. What assumptions did we make that may affect our results? How would you change this lab to address these issues? **


 * CONCLUSION**

= Elastic and Inelastic Collisions = __Honors Physics Period 2__ __3/28/11__

What is the relationship between the initial momentum and final momentum of a system?
 * PROBLEM**

To find out whether or not the Law of Conservation of Momentum holds true in different crash scenarios.
 * PURPOSE**

The initial momentum will be equal to the final momentum in each different crash scenario. We are able to come up with this because of the Law of Conservation of Momentum.
 * HYPOTH****ESIS**

Dynamics track, 2 carts, 2 motions detectors, 2 USB links, masses
 * MATERIALS**

1. Set up motion sensors at each end of the track and connect both to laptop 2. Perform trials with different crash scenarios using 2 carts 3. Record data onto Excel from DataStudio
 * PROCEDURE**

These are pictures of the setup of a typical trial for this lab. media type="file" key="BTM.mov" width="240" height="240" This is a video of a head-on collision where the carts start out separated and then stick together after impact.

This is the data table of all of our calculated and gathered information. These are the graphs of a trial for a head-on collision in which the carts stick together.
 * DATA**


 * CALCULATIONS**






 * ANALYSIS QUESTIONS**
 * 1) **Is momentum conserved in this experiment? Explain, using actual data from the lab.**
 * 2) **When carts of unequal masses push away from each other, which cart has a higher velocity? Explain why this is.**
 * 3) **When carts of unequal masses push away from each other, which cart has more momentum?** Under perfect conditions (no friction, all wheels work perfectly, etc.), the heavier cart has more momentum. The carts would be going at the same speed, but the heavier mass would cause for a larger momentum.
 * 4) **Is the momentum dependent on which cart has its plunger cocked? Explain why or why not.** Yes, the momentum is dependent on which cart has its plunger cocked. The momentum for the cart without the plunger will be greater than the one with the plunger. This is because the one without the plunger will get a larger initial push than the other cart, making its change in velocity greater than the other cart.

**CONCLUSION**

= Measuring Crush Energy = __Honors Physics Period 2__ __3/21/11__

What is the total energy that causes an aluminum can to be crushed? How will the velocity be effected by changing initial heights?
 * PROBLEM**

To find the crush energy from damage measurements on an aluminum soda can being used to model an automobile. To find how altering the height effects the velocity right before the ball hits the can.
 * PURPOSE**

The total crush energy is equal to the initial kinetic energy of the metal ball (striking vehicle). As the initial height increases, so will the velocity at contact.
 * HYPOTHESIS**

Metal ball bearing, soda can, meterstick, laptop with Excel
 * MATERIALS**

1. Drop a metal ball onto a soda can making a dent 2. Trace the dent on the soda can onto a piece of paper and cut it out 3. Divide the crush profile into 5 different sections on the paper 4. Measure the length and depth of each section 5. Using the measurements and the constants given, find the crush energy for each section 6. Add up the 5 different crush energies to find the total crush energy
 * PROCEDURE**


 * DATA**
 * CALCULATIONS**








 * Error**





We cannot know for sure if our first hypothesis was proven correct. The first hypothesis was that that the crush energy is equal to kinetic energy. To prove that our total crush energy and kinetic energy were the same, we used both the crush-energy equation to find the amount of crush energy for each crush zone. Then, we added it up to find the total crush energy and plugged it into the kinetic energy equation, solving for velocity. Then, we compared that calculated velocity with the velocity derived from the work energy equation. If these velocities were equal, then the crush energy and the kinetic energy must be interchangeable. However, our percent difference for velocities from both of our trials were extremely high, at 180.2% and 176.5%. Since the percent difference is so high, there is no telling if this relationship is actually true or not. Part of the reason for this large difference is because the equation to calculate the crush energy is not completely accurate. In addition, human error in measuring the depth and width of each crush zone is a cause for percent difference, so these two factors contributed greatly to the large error. Our second hypothesis, that as the initial height increases, the velocity will, too, was proven to be true. In the trial where we dropped the ball from a higher distance, our calculated velocities (both by the KE equation and the work-energy equation) were higher than the corresponding velocities for the trial where we dropped the ball from a lower height. = =
 * CONCLUSION**