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I recently saw a video ( watch it 0.5x speed ) of a slanted coconut tree on the bank of a river in India breaking due to the weight of the kids who climbed on it.

The tree seems to have broken near the bottom and it fell down immediately like it has no inertia. While kids who were sitting on the tree were clearly suspended in air for a split second which can be seen in the video.

My question is, why did it seem like the tree did not have inertia? Since the tree is more massive than the kids, the tree should have more inertia and a greater tendency to stay at rest than the kids. But it was the opposite.

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  • $\begingroup$ Does this answer your question? Do you feel more impact force when falling straight down or tipping over? $\endgroup$
    – John Rennie
    Commented Jul 27, 2023 at 16:07
  • $\begingroup$ Inertia is not the tendency to stay suspended in the air before free-falling. The kinematic laws of motion are the same regardless of your weight. I would say the difference we see might have to do with the fact that the tree's motion has started by it snapping under the effect of the weight of the people. It didn't drop as if it's support went missing like the people did. $\endgroup$
    – Karim Chahine
    Commented Jul 27, 2023 at 16:13
  • $\begingroup$ Welcome to the stack exchange and this is a good question. Looking at the suggested answer, you have to get to the very end of John's answer where he says "This seems counterintuitive, but it's because left to itself the ladder would rotate faster than the combined system of you and the ladder. In effect the ladder is accelerating you as you and the ladder fall. That's why the final velocity is higher." So because the tree is rotating, it is moving faster than just falling. This would be why the men hang for a split second. $\endgroup$
    – foolishmuse
    Commented Jul 27, 2023 at 16:14
  • $\begingroup$ If this question is reopened I will post the following as answer. Chimney demoltion has features similar to the situation you describe. There is a distinctive pattern: tall chimneys fracture about 1/3 to halfway up. If the chimney would be perfectly rigid then that rigidity would force the top of the chimney to accelerate harder than the 9.8 $\tfrac{m}{s^2}$ of gravity. Having watched the video with the tree: I concur with Karim Chahine: that tree shows extreme acceleration, that is not a fall; some extreme force whips that tree down. $\endgroup$
    – Cleonis
    Commented Jul 27, 2023 at 17:27
  • $\begingroup$ I watched at 1/4 speed, and I don't agree that the kids were "suspended in the air for a split second." I think they immediately started to fall and, that the "suspension" is an illusion caused by the fact that the kids were merely accelerated by gravity while the tree trunk clearly was accelerated by something much stronger. Unfortunately, whatever caused the trunk to whip down so fast was outside the frame of the video, and I don't read whatever that language is in the comments, so I can offer no suggestions about that. $\endgroup$
    – Solomon Slow
    Commented Jul 27, 2023 at 17:46

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This appears to be a wonderful - albeit imprecise - supersized version of the the classic hinged stick and falling ball physics demo, where the gravitational force effectively acting on the stick's centre-of-mass creates a torque around the end resting on the floor which accelerates the tip faster than g as the falling stick rotates.

In slow motion, the falling ball lags behind the falling tip, briefly creating the illusion of suspension. The tip will be accelerated faster than g when the angle of the stick with the floor exceeds 35°, but I won't do the math here because it is a classic homework problem. As discussed in the answer to Why does a ruler continue to slide after toppling?, when that angle exceeds 48°, the stick also starts moving horizontally from its original position, increasing the separation between the stick and the ball/coins. For more related analysis, look at the question and answers to Will a falling rod stay in contact with the frictionless floor?.

This effect is especially clear in this video of a variant where coins are rested on a metre stick with one end resting on a table and the other end is released.

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