4 ms·
Hmm.. Would have liked to see more details about the accident itself. The cannonball was cast iron? Any estimation about speed and weight? Actually the biggest
by darklajid 15y ago
Hmm.. Would have liked to see more details about the accident itself. The cannonball was cast iron? Any estimation about speed and weight?
Actually the biggest surprise were the walls of the house shown (mostly the exterior wall): Is this a brick and mortar house/wall? Or is this wood/insulation mostly?
Edit: In fullscreen that looks to be a wall made of concrete, with a network of iron/steel to support it? Even if it's a ~thin~ wall by some standards, this is a lot stronger than I initially guessed.
- luastoned 15y agoJust wood and insulation.
- viggity 15y agoThe video said the cannon ball was the size of a softball.
- fr0sty 15y agoThe house has a stucco exterior. Rigid foam insulation clad with a metal mesh covered with a thin layer of what is basically concrete.
- unwind 15y agoIf it was a regulation-size softball made of average-density grey iron, I get 103.9 kg for the mass.
- maxerickson 15y agoI get about 4 kg. (It appears you may have used the 12 inch circumference from your softball regulations as the radius of the ball)
- deleted 15y ago[deleted]
- cbr 15y agoYou might want to practice comparing results of calculations you make to what seems intuitively likely. I think you would find it's a very helpful in catching errors.
- code_duck 15y agoSupposedly they were "trying to figure out how fast a cannonball would travel". Presumably they knew the mass, density and shape... and the force of the explosives being used. Perhaps someone should tell them about physics, it would save some trouble.
- NegativeK 15y ago> Perhaps someone should tell them about physics Are you referring to the hosts or the general public that the hosts enjoy educating?
- code_duck 15y agoI was referring to the hosts. I'm neither an explosives expert, nor a physicist, but it seems to me that there would be simpler ways of determining this. Of course, the purpose is vaguely informative entertainment, not scientific research.
- Symmetry 15y agoWith low explosives like those used in cannons figuring out the force can be pretty tricky. This isn't an adiabatic expansion, the force experienced on the ball will depend on how fast the ball is moving. The rate at which the explosive burns depends on the heat inside the chamber which depends on the pressure. The burn rate and rate at which the cannonball leaves, plus a modifier based on how much escapes through the ignition hole, governs the pressure. I really wouldn't trust any calculation of all of the above without experiment.