Chapter 8 Momentum Impulse and Collisions Power Point

Goals for Chapter 8 • To determine the momentum of a particle • To

Introduction • If you watch a football game, you’ll see collisions, tackles, many men

How does momentum relate to mass and velocity? • Understanding momentum begins with the

Compare momentum and kinetic energy • The impulse–momentum relationship depends on duration of an

Duration of an impact • Figure 8. 6 and Figure 8. 7 are both

Like energy, momentum also has conservation rules • Refer to Figure 8. 8. No

Don’t forget that momentum is a vector • Refer to Figure 8. 10 at

Objects colliding along a straight line • Consider the collision in Example 8. 5.

Now, consider a two-dimensional collision • Considering even just two dimensions makes the problem

Elastic compared to inelastic Copyright © 2008 Pearson Education Inc. , publishing as Pearson

Completely (or nearly) inelastic collisions • Cars are designed to crumple and absorb as

The ballistic pendulum • This can be demonstrated with a 4 4 block and

A possible simple model for automobile accidents • Refer to Example 8. 9 and

Elastic collisions—Figure 8. 21 • Billiard balls are a very good example of objects

Solve a problem related to the “break” • Consider Example 8. 10, referring to

A two-dimensional elastic collision • Consider Example 8. 12. Copyright © 2008 Pearson Education

Center of mass • Refer to Example 8. 13 considering a water molecule. Copyright

Many centers of mass Copyright © 2008 Pearson Education Inc. , publishing as Pearson

Tug-of-war without friction (on the feet) • Refer to Example 8. 14. Copyright ©

Rocket propulsion is a spectacular application! • Look at Figure 8. 32. • Examples

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Chapter 8 Momentum, Impulse, and Collisions Power. Point® Lectures for University Physics, Twelfth Edition – Hugh D. Young and Roger A. Freedman Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Goals for Chapter 8 • To determine the momentum of a particle • To add time and study the relationship of impulse and momentum • To see when momentum is conserved and examine the implications of conservation • To use momentum as a tool to explore a variety of collisions • To understand the center of mass • To study rocket propulsion Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Introduction • If you watch a football game, you’ll see collisions, tackles, many men colliding at once, maybe just two in an open area. Are these situations different? • Newton told us the forces result in acceleration of a mass. We will now study two new points of view— momentum and impulse. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

How does momentum relate to mass and velocity? • Understanding momentum begins with the simple relationship that momentum is equal to mass multiplied by velocity. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Compare momentum and kinetic energy • The impulse–momentum relationship depends on duration of an impact while the work-energy theorem focuses on the distance of force application. • Refer to Conceptual Example 8. 1. • Consider Example 8. 2, the figure below at right completes that question. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Duration of an impact • Figure 8. 6 and Figure 8. 7 are both image/diagrams related to sports. They are, in fact, of the same duration. The bottom figure assists the setup of Example 8. 3. • Consider Example 8. 3. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Like energy, momentum also has conservation rules • Refer to Figure 8. 8. No forces are at play save those from the astronauts. • Refer to Figure 8. 9. Many forces are at work. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Don’t forget that momentum is a vector • Refer to Figure 8. 10 at right. Then consider Problem-Solving Strategy 8. 1. Figure 8. 11 below will assist you to work through Example 8. 4. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Now, consider a two-dimensional collision • Considering even just two dimensions makes the problem much more intricate. • Consider Example 8. 6. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Completely (or nearly) inelastic collisions • Cars are designed to crumple and absorb as much energy as possible so the passengers do not need to. • Consider Example 8. 7 and Figure 8. 17 at right below to help you. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

The ballistic pendulum • This can be demonstrated with a 4 4 block and a. 22 caliber rifle. Most schools now prohibit firearms on campus. • Consider Example 8. 8 and Figure 8. 18 at right to assist you. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Solve a problem related to the “break” • Consider Example 8. 10, referring to Figure 8. 24 below. • Refer also to Example 8. 11. Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley

Rocket propulsion is a spectacular application! • Look at Figure 8. 32. • Examples 8. 15 and 8. 16 both foreshadow a NASA career calculation. Graduation isn’t that far away! Copyright © 2008 Pearson Education Inc. , publishing as Pearson Addison-Wesley