LVang+-+L11+-+Ballistic+Pendulum+Research+Lab

Lue Vang Mr. Kellogg AP Physics - Pd. 7 23 January 2012 Performed On: 23 January 2012 **Ballistic Pendulum Research Lab**

A ballistic pendulum is a physics apparatus consisting of a launcher, a projectile, and a pendulum. See Figure 1.01

The launcher is located in the lower left corner of the image. It shoots a projectile, the circular object, into a basket-like compartment. The force of the projectile will cause the basket to move, but, being attached to a fix axel, the pendulum will move forward in a circular swinging motion. At the end of the basket's motion, a catching mechanism will catch the pendulum at its maximum height. Notice the maximum height is measured in reference to the center of gravity in the swinging mass.
 * Figure 1.01**

After utilizing the fascinating piece of engineering, the scientist will be able to know mass (g), acceleration due to gravity (9.8 m/s^2), original potential energy (relatively 0 J), final potential energy (J), final kinetic energy (0 J), and total mechanical energy, which is equal to the final potential energy. In this case, the unknown variable will be the initial velocity (m/s) of the projectile, which can be found using the final potential energy and the formula for kinetic energy (1/2mv^2).

Basically, the ballistic pendulum will allow physicians have fun in trying to evaluate the initial velocity of the projectile with the studies of the laws of conservation of momentum and mechanical energy. The ballistic pendulum will give a dramatic physical example of the two laws. In general, this contraption mainly deals with the conservation of momentum and mechanical energy. But although the total mechanical energy of the system is relatively conservative, the ballistic pendulum demonstrates that kinetic energy is not conserved; instead, it'll be transformed into potential energy as the mass reaches maximum height and stops. With the law of conservation of energy, since the total mechanical energy before and after the event are equal, the collected data can be used to find unknown data using the equations of conservative mechanical energy. For example, since the ME1 = ME2, and ME2 is simply mgh. Since, mass, acceleration due to gravity, and height are known, to find the initial velocity of the projectile, simply solve for (v) in 1/2mv^2 = mgh.

A real ballistic pendulum looks as such:

Sources: [|http://www.cabrillo.edu/~cfigueroa/4B/4Blabs/sample_formal_report.pdf] [] [] http://www.sciencefirst.com/Rotation_Oscillation.html