This video show us that the bottom of a dropped slinky hovers dramatically in the air. Through this situation some physicists provided new insight into this phenomenon. Shimon Kolkowiz who is a physics graduate student at Harvard University in Cambridge said, “When we hold one end of a Slinky, letting it hang down and then drop it, it turns out the bottom stays suspended, levitating in air for some period in time.” Also he calculated that the bottom of this metal slinky would remain suspended for approximately three-tenths of a second. As a result from this video, the Slinky stretches out, quickly reaching a condition(equilibrium). In witch the downward force of gravity is balanced by the upward tension of the coils above it. When the top of the Slinky collapses, the coils slam into each other. The weaker gravitational field wouldn’t stretch the slinky as much, so the spring would compress more near by the bottom when dropped, it takes some 0.3 seconds to get there. Kolkowiz found out the Slinky’s center of mass, but is always located in between the top and bottom of the toy. So there is no violation of any of Newton’s laws or Galileo’s observations about falling objects. I was interested in this video because if was right after we learned about Newton’s law.
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In the article I also read about what would happen if this experiment was done on Jupiter. Since the gravitational force is greater, it would stretch the slinky out longer. Even though it would be stretched out longer, the recoil would be faster so the levitation time remains the same. The center of mass of the slinky still accelerates towards the ground according to gravity. The only two factors that affect the levitation time are mass and stiffness of the coils.
This article was very interesting to read. It’s amazing how we can learn so many things about physics in very simple devices, like slinkies. In just one little children’s toy, we can learn about so many different areas of physics.
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