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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.

wedneday
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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.

David Bailey
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