1. Physics 218: Mechanics Instructor: Dr. Tatiana Erukhimova Lecture 26

2. 9080706050 Average = 63.2 High 97 Low 13 A? B?C?

3. Center of Mass

4. Find the position of the center of mass of the system of the sun and Jupiter. (Since Jupiter is more massive than the rest of the planets put together, this is essentially the position of the center of mass of the solar system.) Does the center of mass lie inside or outside the sun?

5. Motion of the Center of Mass

6. The center of mass of a system moves as if all of the mass of the system were concentrated at that point and as if all of the forces were acting at that point There is only the external forces that affect the motion of the center of mass ( ) Only external forces affect the motion of the center of mass

7. Momentum is a vector! Vector equation!

8. If

9. Conservation of Momentum If there is no external force on a system, then the total momentum of the system is a constant

10. True in X and Y directions separately!

11. Have a great day! Hw: Chapter 10 problems and exercises Reading: Chapter 10