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CHAPTER
Systems of Particles 10
CONCEPTS IN CONTEXT
Concepts
in
Context While this high jumper is passing over the bar, he bends backward and
keeps his extremities below the level of the bar.This means that the aver- 10.1 Momentum
age height of his body parts is less than if he were to keep his body straight, 10.2 Center of Mass
and he requires less energy to pass over the bar.
10.3 The Motion of the Center
The concepts introduced in this chapter permit us to examine in detail
of Mass
several aspects of the motion of the jumper:
10.4 Energy of a System
? The body of the jumper is a system of particles. Where is the average of Particles
position of the mass of this system of particles when the body is in a
straight configuration? How does this change when the jumper
reconfigures his extremities? (Example 8, part (a), page 322)
? What is the gravitational potential energy of a system of particles, and
how much does the jumper reduce his potential energy by bending his
body? (Page 321 in Section 10.2 and Example 8, part (b), page 322)
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