Will Dropping a Cinder Block Really Only Destroy One Block?

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Discussion Overview

The discussion centers around the effects of dropping a cinder block onto a stack of other cinder blocks, specifically whether the impact will only destroy the dropped block or if it will also cause damage to the blocks below it. Participants explore the relationship between drop height, impact energy, and resulting damage to the blocks, considering various physical principles.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants argue that a dropped cinder block will only destroy itself if dropped from a very low height, while higher drops will lead to more blocks being damaged due to increased impact energy.
  • One participant explains that the energy dissipated during impact generates shock waves, which can cause damage to the blocks, starting from the top block of the stack and potentially affecting those below as the drop height increases.
  • Another participant emphasizes that the exact outcome depends on various factors, including the blocks' composition, size, density, elasticity, and surface characteristics, suggesting that a precise model would require extensive information.
  • There is mention of Newton's laws, with one participant asserting that another misunderstands these laws in the context of the discussion about impact and damage.

Areas of Agreement / Disagreement

Participants do not reach a consensus; there are competing views on the extent of damage caused by the dropped block and the implications of physical laws on the situation.

Contextual Notes

The discussion highlights the complexity of modeling the impact scenario, noting that many variables must be considered to accurately predict outcomes, which remains unresolved.

Totaro17
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I have been debating somebody and he says that if you drop one cinderblock from ANY height(onto 9 other ones) it will only destroy one cinderblock because it destroys itself in the process.I believe the higher up you drop, more blocks will be destroyed. Can someone tell which is correct and(most importantly) WHY??
 
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The faster the impact the greater amount of energy has to be dissipated on impact, so there will be a correspondingly greater amount of damage, primarily as a result of shock waves generated in the rigid and brittle blocks.
If you drop from just 1cm the shock waves will be small so there will be very little if any damage to any block.
As you increase the drop height damage will get more severe until the dropped block is destroyed every time, and you will begin to see increasing amount of damage occurring to the top block of the stack.
Eventually the impact energy will become great enough that the top block of the stack is also destroyed every time.
Increasing the impact energy still further would result in blocks further down in the stack taking damage too.
 
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rootone said:
The faster the impact the greater amount of energy has to be dissipated on impact, so there will be a correspondingly greater amount of damage, primarily as a result of shock waves generated in the rigid and brittle blocks.
If you drop from just 1cm the shock waves will be small so there will be very little if any damage to any block.
As you increase the drop height damage will get more severe until the dropped block is destroyed every time, and you will begin to see increasing amount of damage occurring to the top block of the stack.
Eventually the impact energy will become great enough that the top block of the stack is also destroyed every time.
Increasing the impact energy still further would result in blocks further down in the stack taking damage too.
rootone said:
The faster the impact the greater amount of energy has to be dissipated on impact, so there will be a correspondingly greater amount of damage, primarily as a result of shock waves generated in the rigid and brittle blocks.
If you drop from just 1cm the shock waves will be small so there will be very little if any damage to any block.
As you increase the drop height damage will get more severe until the dropped block is destroyed every time, and you will begin to see increasing amount of damage occurring to the top block of the stack.
Eventually the impact energy will become great enough that the top block of the stack is also destroyed every time.
Increasing the impact energy still further would result in blocks further down in the stack taking damage too.
Thank you so much for your reply! I said the same thing, almost verbatim to this person. He said I was wrong because of Newton's 3rd law. I told him that he misunderstands the law and there is more going on (1st and 2nd law, along with other physics). Can you possibly explain it in a more technical way( using equations and or modeling). Again THANK YOU!
 
To give a precise model of what would occur, so you could estimate for example the drop height at which the the first block breaks - that would require quite a lot of additional information about the exact composition of the blocks, their size, their density, elasticity (are they complete rigid or can they flex a small amount?), even their exact shape would be a factor, are the block surfaces completely smooth or not?, and probably more, it could quickly get very messy.

The main point is that the collision generates shock waves in a rigid material, and rigid materials tend to shatter in these circumstances.
Bigger shock waves at the point of impact will cause more damage at the impact site, and they also will travel further from the impact site with more potential to cause damage some distance away.

If you really do need a detailed accurate predictive model for some reason there are people on this site who would be better qualified to have a go at that than me, but it would be a considerable task to do so.
 
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