1. Physics 2215: The Ballistic Pendulum Purpose  Solve a problem by using Kinematics (Newton’s Laws, Equations of Motion) Energy/Momentum Conservation.  Use techniques learned in earlier labs: Measuring techniques Error calculation Statistics

2. Physics 2215: The Ballistic Pendulum A simple example of kinematic versus energy conservation approaches. Dropping a ball from a height of 1m. Calculate the velocity just before the impact on the floor. h=1m v o = 0 v f = ? y y = 0

3. Physics 2215: The Ballistic Pendulum Kinematic Approach y y = 0

4. Physics 2215: The Ballistic Pendulum Energy Approach y y = 0 Potential Energy Kinetic Energy

5. Physics 2215: The Ballistic Pendulum Ballistic Pendulum Apparatus Spring loaded apparatus that “shoots” metal ball. Pendulum that catches the ball and is able to swing after the impact.

6. Physics 2215: The Ballistic Pendulum A. Determine the Speed of the Metal Ball Using a Kinematic Approach Idea: 1) Remove the pendulum part and simply shoot the ball horizontally off the table 2) Measure the horizontal and vertical distances from launch to impact on the floor. 3) Calculate v o. vovo x y

7. Physics 2215: The Ballistic Pendulum B. Determine the Speed of the Metal Ball Using a Momentum Conservation and Energy Conservation Approach Idea: 1)Shoot the metal ball into the pendulum so that the metal ball gets stuck in it. 2)Measure the maximum angle the pendulum will swing up after the impact. 3)Use conservation of angular momentum and conservation of energy to determine v o. vovo v Before impact: After impact: L conserved

8. Physics 2215: The Ballistic Pendulum After impact: v  max At maximum of the swing: Energy conserved

9. Physics 2215: The Ballistic Pendulum Determining the Moment of Inertia of Pendulum with Ball (I system ) 1) Disconnect the pendulum and reattach it on the other side so that it can swing freely. 2) Let the pendulum swing (with the ball in it) and measure the period of oscillation. 3) Determine the moment of inertia I using this formula: Hint: You can get l cm by balancing the pendulum on the center of mass: l cm