Ballistic Pendulum
Partners: Mary Schaude, Kyle Collins, and Hunter McCabe
Date: 2/11/15-2/20/15
Date: 2/11/15-2/20/15
Purpose
The purpose is to determine the velocity of the steel ball.
Theory
The Law of Conservation of Momentum states that in a collision between two objects, the momentum before and after the collision are equal. Any momentum lost by the first object is gained by the second object. Momentum is conserved. Below is the equation for the Law of Conservation of Momentum.
The Law of Conservation of Energy states that energy can't be created or destroyed but it can be changed into another form or transferred to another object. Below is the equation for the Law of Conservation of Energy.
Cosine is the side adjacent to the angle over the hypotenuse. Below is the trigonometric function for cosine.
Below is the equation that will be used to find out V1. First, you must set the equation for the Law of Conservation of Momentum to solve for V1. Next, you must solve the Law of Conservation of Energy to solve for V' and then substitute that equation for V' in the Law of Conservation of Momentum equation. Finally, reconfigure cosine so that it is set to find height(h) then substitute that into the Law of Conservation of Momentum equation.
Experimental Technique
Apparatus:
-Computer -Ballistic Pendulum -Steel Ball -Launcher -Stand -Photogates -Data Studios -Mass -Calculator -Digital Adapter -Rotary Motion Sensor |
Procedure:
1. Find the center of mass on the pendulum. 2. Set up the apparatus. 3. Set up Data Studios. 4. Set Data Studios to read angle. 5. Place steel ball into launcher. 6. Push it back to number of clicks specified. (Hunter 1 click, Kyle 2 clicks, Mary 3 clicks) 7. Launch the steel ball into pendulum. 8. Record maximum angle given by Data Studios. 9. Repeat Steps 4-7 until a total of 10 trails are done. 10. Calculate the velocity. 11. Remove the pendulum. 12. Set up the Photogates. 13. Set Data Studios to read velocity. 14. Do Steps 4-7 until 10 trials are completed. 15. Have Hunter catch the steel ball in the palm of his hand for each trial. 16. Record the velocity given by Data Studios. 17. Examine Hunter's hand to make sure that bruises and indents are visible. 18. Calculate the percent difference. |
Data
Analysis
Conclusion
Our lab had gone fairly well. The distance to center of mass, or radius, was about 35.5 cm. The mass of the steel ball was 17.1g and the mass of the pendulum was 148.4g. The angles for my test runs were either 18.0 degrees or 17.7 degrees. The pendulum went to a height of either 1.74 cm or 1.68 cm depending on the angle. The velocity we calculated was either 5.65 m/s or 5.55 m/s. Using the Photogates, the measured velocity was between 5.54 m/s and 5.58 m/s. Finally, the percent difference was between 0.180% and 1.97%.
Out of all the measurements, the radius has the greatest potential to be wrong. We has to measure to the point the pendulum balanced at. However, it was difficult to measure since it would slide off the table or any flat edge. It was also difficult to measure since we could not easily measure it without the pendulum moving. We could have probably fixed this by using something that had a sharp angle pointing upwards to set the pendulum on so we could balance it properly.
The next measurement that is most likely to be wrong is the angle. Since it was such a small angle and the rotary motion sensor can only measure to a certain extent, the real angle may not have been recorded.
Out of all the measurements, the radius has the greatest potential to be wrong. We has to measure to the point the pendulum balanced at. However, it was difficult to measure since it would slide off the table or any flat edge. It was also difficult to measure since we could not easily measure it without the pendulum moving. We could have probably fixed this by using something that had a sharp angle pointing upwards to set the pendulum on so we could balance it properly.
The next measurement that is most likely to be wrong is the angle. Since it was such a small angle and the rotary motion sensor can only measure to a certain extent, the real angle may not have been recorded.
References
http://examples.yourdictionary.com/law-of-conservation-of-energy-examples.html
http://www.physicsclassroom.com/class/momentum/Lesson-2/Momentum-Conservation-Principle
http://www.physicsclassroom.com/class/momentum/Lesson-2/Momentum-Conservation-Principle