Its interesting to note how little we know about gravity.... -AK
Holy levitating Slinky!
June 19, 2012
From: http://kottke.org/12/06/holy-levitating-slinky
In this series of slow motion clips, you can see that if you hold a Slinky by one end and drop it, the bottom end doesn't actually move until the top end catches up with it.
I've watched this like six times and it drops my jaw every time...the bottom of the Slinky JUST. DOES NOT MOVE. Here's the scientific explanation:
The explanation that "it takes time for the bottom of the slinky to feel the change" might work ok, but it isn't the best.
Then why doesn't the bottom of the slinky fall as the top is let go? I think the best thing is to think of the slinky as a system. When it is let get, the center of mass certainly accelerates downward (like any falling object). However, at the same time, the slinky (spring) is compressing to its relaxed length. This means that top and bottom are accelerating towards the center of mass of the slinky at the same time the center of mass is accelerating downward.
(via @stevenstrogatz)
Update: See also The Physics of a Falling Slinky. (via @jeffhellman)
Tuesday, June 19, 2012
4 comments:
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Cool!
ReplyDeletegee it's a lot ore simple than they make it out to be.
ReplyDeletethe spring decompression creates an upwards force that is nearly equal to the downward gravitational force so the bottom of the slinky will not move downward until the upward force of decompression reduces to the point of being less than gravity.
Adding a ball to the bottom adds to the downward force thus the bottom WILL START MOVING sooner. As the upward force is more quickly reduce to less than the downward force.
It's not that hard with simple logic and observation\understanding.
Just like the 6 million dollar man feats of strength were obviously impossible because the stress of lifting say a car would have to be transferred to the non-bionic parts of the body (chest, neck hips), which being normal would have collapsed torn or broken under the super sized weight.
When I watched this spiral falling I realised how long will it take for a neoliberal bankers lead government in Latvia (EU) to fall - untill the spiral from the Fall of Central Banksters (in USA) will reach the spiral of the G5 and after that the enslaved European province, whose people in spite of their gravitational force and need for food are now pendling in the air.
ReplyDeleteAbsurd, Latvian economy as (EU)success story measures... Just like lower end of the spiral sitting in the air.
ps. AK, keeping you in heart...
Sounds like centripetal force of the spinning slinky could be creating an anti-gravitic effect. I'm comparing this to spinning salmon flying up.
ReplyDelete