4.20. Elastic Force http://www.ck12.org
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/5024You can do some virtual bungee jumping at this URL:
http://www.youtube.com/watch?v=eaICwFMHcaY
Q: What force stretches the bungee cord after the jumper jumps? When does the bungee cord snap back to its
original shape?
A: After the bungee jumper jumps, he accelerates toward the ground due to gravity. His weight stretches the bungee
cord. As the bungee cord stretches, it exerts elastic force upward against the jumper, which slows his descent and
brings him to a momentary stop. Then the bungee cord springs back to its original shape, and the jumper bounces
upward.
Using Elastic Force
Elastic force can be very useful and not just for bungee jumping. In fact, you probably use elastic force every day.
A few common uses of elastic force are shown in theFigure4.37. Do you use elastic force in any of these ways?
FIGURE 4.37
Q: How does the resistance band work? How does it use elastic force?