Ballistic Pendulum
Partner: Schyler Cordova
Date: 3/20/14
Date: 3/20/14
Purpose:
In this lab, the purpose is to use the maximum angle of the pendulum to determine the initial velocity of the projectile.
In this lab, the purpose is to use the maximum angle of the pendulum to determine the initial velocity of the projectile.
Theory: In a perfectly inelastic collision momentum is conserved. When the ball and the pendulum begin to move together energy is conserved from that point to the point where the pendulum reaches its maximum angle. Therefore, KE = PE. To find PE the height of the pendulum at its maximum angle must be determined by using the information in image 2.
Experimental Technique:
1. Use foam to set up a trap to catch the projectile. (See image 1)
2. Set up the pendulum and projectile launcher with the rotary motion sensor.
(See image 2 & 3)
3. Measure the mass of the pendulum and the projectile, as well as, the length of the pendulum.
4. Prepare Data Studio for the experiment.
5. Set up the projectile launcher with the projectile at the first click, start Data Studio, and collect data for the first launch.
6. Set up the projectile launcher with the projectile at the second click, start Data Studio, and collect data for the second launch.
7. After collecting the data with the pendulum, move the pendulum and set up the photogates. (See image 4)
8. Configure Data Studio with the photogates and record the initial velocity of the projectile at the settings used in steps 5 and 6.
9. Use the conservation of momentum and energy equations to mathematically determine the initial velocity of the projectile.
10. Compare the calculated value to the value recorded in Data Studio and calculate percent difference.
1. Use foam to set up a trap to catch the projectile. (See image 1)
2. Set up the pendulum and projectile launcher with the rotary motion sensor.
(See image 2 & 3)
3. Measure the mass of the pendulum and the projectile, as well as, the length of the pendulum.
4. Prepare Data Studio for the experiment.
5. Set up the projectile launcher with the projectile at the first click, start Data Studio, and collect data for the first launch.
6. Set up the projectile launcher with the projectile at the second click, start Data Studio, and collect data for the second launch.
7. After collecting the data with the pendulum, move the pendulum and set up the photogates. (See image 4)
8. Configure Data Studio with the photogates and record the initial velocity of the projectile at the settings used in steps 5 and 6.
9. Use the conservation of momentum and energy equations to mathematically determine the initial velocity of the projectile.
10. Compare the calculated value to the value recorded in Data Studio and calculate percent difference.
Data:
Analysis:
Conclusion:
The purpose of this lab was to determine the initial velocity of the projectile by using the maximum angle of the pendulum. The measured initial velocity of the projectile at the first click was 5.52 m/s and the calculated initial velocity was 3.26 m/s. The velocities for the first click had a percent difference of 51%. At the second click, the measured initial velocity was 7.25 m/s and the calculated initial velocity was 4.63 m/s. The velocities for the second click yielded a 44% difference. The large percent differences are due to error in the experiment. One possible problem is that the projectile may have been able to move a little once it hit the pendulum which would affect the momentum transfer, as well as the energy of the system. Another possible issue is that the center of mass may have been off, which would have caused the pendulum to not function properly.
The purpose of this lab was to determine the initial velocity of the projectile by using the maximum angle of the pendulum. The measured initial velocity of the projectile at the first click was 5.52 m/s and the calculated initial velocity was 3.26 m/s. The velocities for the first click had a percent difference of 51%. At the second click, the measured initial velocity was 7.25 m/s and the calculated initial velocity was 4.63 m/s. The velocities for the second click yielded a 44% difference. The large percent differences are due to error in the experiment. One possible problem is that the projectile may have been able to move a little once it hit the pendulum which would affect the momentum transfer, as well as the energy of the system. Another possible issue is that the center of mass may have been off, which would have caused the pendulum to not function properly.
References:
Ballistic Pendulum. (n.d.). Ballistic Pendulum. Retrieved April 6, 2014, from http://hyperphysics.phy-astr.gsu.edu/hbase/balpen.html#c2
Ballistic Pendulum. (n.d.). Ballistic Pendulum. Retrieved April 6, 2014, from http://hyperphysics.phy-astr.gsu.edu/hbase/balpen.html#c2