Pedagogy in Action > Library > Using Direct Measurement Videos to Teach Physics > Example Activities > Analyzing a Direct Measurement Video of a Ballistic Pendulum

Analyzing a Direct Measurement Video of a Ballistic Pendulum

by Christopher R. Smith
Lake Mills High School

Based on the video from Peter Bohacek, Henry Sibley High School


Ballistic Pendulum is an activity that utilizes the Law of Conservation of Energy and the Law of Conservation of Momentum to determine the velocity of a Peanut M&M that is shot from a cannon into a cup. The activity walks students through the problem step by step to get the outcome, asking conceptual and math problems along the way to obtain the final product: the velocity of the Peanut M&M.

Learning Goals

Students will understand the concept of the Law of Conservation of Momentum in this activity.

Students will need to recall the concept of the Law of Conservation of Energy.

Instructors can remove steps to make it more of a critical thinking skill.

Context for Use

This situation is appropriate for helping students identify conservation of energy and momentum. This is an activity is a guide that helps students walk through the problem and see how concepts can be combined mathematically and applied to a situation. It is a way of helping assist problem solving and can be used as a 20-30 minute facilitated activity, homework, or classroom discussion. Students would need a computer to view the file. The Law of Conservation of Energy is best mastered before doing this activity, and the concept or equations of momentum is good to have been seen first. The more steps that is taken out, the more difficult the problem will be. Without know the concept of momentum or seeing it, it may be difficult to perform the activity. This would be best suited as a reinforcement than an introduction to momentum.

Description and Teaching Materials

I would start off my class by first handing out the activity and having students answer the pre-activity problems. I would discuss them with the class to make sure that everyone is on the same page. Then, I would have them get on a computer with quicktime and try to solve the problem. I would walk around and facilitate students and help them as they go.

Worksheets are Ballistic Pendulum Activity Worksheet Ballistic Pendulum Activity Sheet (Microsoft Word 2007 (.docx) 18kB Jul13 12) and Ballistic Activity Answer Key Ballistic Pendulum Activity Sheet Key (Microsoft Word 2007 (.docx) 39kB Jul13 12)

M&M candy ballistic pendulum (Quicktime Video 1.3MB Jul7 12)

The Answer Key goes through step by step how to each problem with conceptual answers.

Teaching Notes and Tips

I would suggest making sure they have seen some momentum problems before trying to do this assignment.


This would be an informal assessment that I would do, and it would just be based on their answers. I would also typically give a few homework problems that deal with the same concepts of momentum to help reinforce the problem.

References and Resources

M&M candy ballistic pendulum (Quicktime Video 1.3MB Jul7 12)

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