Compare the results of the experiment to what the results should be mathematically. Materials: PASCO ballistic pendulum Metal Ball Electric Scale Stop Watch Photo-gate Computer with DataStudio Ruler Procedure: 1. Measure the mass of the ball 2. Place the ball inside the pendulum arm and find the mass, and the radius from the center of mass to the end of the arm 3. Calculate the period of oscillation using a stopwatch 4. Calculate moment of inertia using the equations shown in results 5. Set up the photogate so the launched ball can pass through it 6.
Launch the ball ten times and find the average initial velocity 7. Calculate angular velocity 8. Launch the ball into the pendulum and record the angle it reaches using the angle measure on the pendulum 9. Repeat step 8 ten times and find the average angle 10. Calculate experimental angular velocity and compare to the number obtained in step 7 Data/Results: Mass of Ball (kg) Mass of Ball + Pendulum (kg) Radius of Ball (m) Radius of Pendulum to Center of mass (m) Av. Launch Angle Period (sec) 0. 055 0. 151 0. 022 0. 3 45. 050 8. 569 1. 209
Calculations: Inertia Conservation of Energy Angular Momentum Here is a table showing the results: Moment of Inertia Angular velocity (COE) Angular Velocity (Ang. Mom. ) 0. 0164 kgm 2 3. 99 rad/s. 8. 62 radis Discussion: Elastic collisions occur when two objects collide and conserve both momentum as well as kinetic energy Inelastic collisions occur when two objects collide, and kinetic energy is not conserved, while momentum is still conserved The quantity of rotation of a body, which is the product of its moment of inertia and its angular velocity.
An object’s center of mass is the point where the distribution of an objects mass is balanced. That mean that the all moments at that point are equal to zero. If a vector quantity is conserved, it means that the sum or product of an initial action must equal to the sum or product of the final action. The results were fairly off. The difference was about double. One issue in the lab was the relatively Judgmental way of measuring period of oscillation, not scientific equipment was really used Just a guy determining when to stop a stopwatch.
Another issue could stem with the photogate. The photogate only measures velocity at a single point on the ball rather than the entire velocity of the ball. Air resistance was also not taken into consideration. Conclusion: model simply has less external factors to influence the results. One other group used a larger ball as well as a faster launch speed in this case, both moment of inertia was increased as well as angular velocity. If a less massive ball or slower launch speed was used the opposite would be achieved.