UNIT 4 Linear Momentum

Developing Understanding

Unit 4 guides students through the connections between force, time, impulse, and linear momentum. This is accomplished with calculations, data analysis, experimental design, and predictions. Learners will employ new models and representations to illustrate the law of conservation of linear momentum for objects and systems, while continuing to use representations introduced in earlier units. Applying the law of conservation of linear momentum allows for deeper analysis of physical situations and addresses misconceptions about Newton’s third law. Students will also be able to relate momentum to kinetic energy, examining when each quantity is conserved.

Building Science Practices

•    1.B
•    2.B
•    2.D
•    3.A

Inquiry-based learning, critical thinking, and problem-solving skills develop best through scientific inquiry experiences with increasing student involvement. In Unit 4, students are encouraged to collect data and design experimental procedures to answer scientific questions. For instance, students may analyze a familiar experiment by writing a plan for observation and data collection. After designing procedures and gathering data, students can practice data analysis by plotting graphs and interpreting best-fit lines to support claims about physical phenomena.

Preparing for the AP Exam

The third free-response question on the AP Physics C: Mechanics Exam focuses on Experimental Design and Analysis. In this section, students must justify the type of data required and develop a strategy for data collection. Because experimental design can pose challenges, scaffolded opportunities to determine the necessary data support learning. The exam also requires students to linearize and analyze data. Practicing experiment design, data analysis, and discussions of error sources throughout the course will help students succeed on the Experimental Design and Analysis (LAB) question.