### Unit 7: Momentum and Collisions

We use the term momentum in various ways in everyday language. We speak of sports teams gaining and maintaining the momentum to win. Generally, momentum implies a tendency to continue on course - to move in the same direction - and is associated with mass and velocity. Momentum has its most important application in analyzing collision problems, and, like energy, is important because it is conserved. Only a few physical quantities are conserved in nature, and studying them yields fundamental insight into how nature works, as we shall see in our study of momentum.

**Completing this unit should take you approximately 12 hours.**

### 7.1: Momentum and Impulse

Read sections 8.1, and 8.2 of "Chapter 8: Linear Momentum and Collisions" (pages 261 to 265). Look over the corresponding conceptual questions on page 282 to test your understanding of the sections.

Try solving these practice problems.

Work on solving problems 1 through 4 from SAC125. The solutions are available, but make a serious attempt to solve the problems before looking at the solutions.

### 7.2: Conservation of Momentum in Collisions

Watch this lecture series, pausing to take notes, before moving on to the reading below.

Read sections 8.3, 8.4, and 8.5 of "Chapter 8: Linear Momentum and Collisions" (pages 266 to 274). Look over the corresponding conceptual questions on page 282 to test your understanding of the sections.

Try solving these practice problems.

This is a classic physics demonstration. Vary the conditions as allowed by the animation and solve the equations of motion based on conservation of momentum and (in the case of elastic collisions) energy. Develop an explanation for any apparent discrepancies.

Work on solving problems 1 through 5 from SAC104. The solutions are available, but make a serious attempt to solve the problems before looking at the solutions.

### 7.3: Collisions in Two Dimensions

Read sections 8.6, and 8.7 of "Chapter 8: Linear Momentum and Collisions" (pages 274 to 280). Look over the corresponding conceptual questions on page 282 and 283 to test your understanding of the sections.

Try solving these practice problems.

### Unit 7 Assessment

Please take this assessment to check your understanding of the materials presented in this unit.

**Notes:****There is no minimum required score to pass this assessment, and your score on this assessment**__will not__factor into your overall course grade.**This assessment is designed to prepare you for the Final Exam that will determine your course grade. Upon submission of your assessment you will be provided with the correct answers and/or other feedback meant to help in your understanding of the topics being assessed.****You may attempt this assessment as many times as needed, whenever you would like.**