If you know that the offending ball weighs more, then you can weigh 3 vs 3, if they balance then measure the other 2 and the heavier one is your ball, if they don't then weigh 2 of the heavier 3 against each other, if they balance it's the left over one otherwise it's the heavier one.
Is it...
The problem doesn't even state what you're trying to achieve with these weighings? It also doesn't state whether you're using a balance or scales.
If you got this from a teacher, I would write an answer discussing the many holes in the question.
Erm, I hate to be a pedant and all, but surely you only need a single ball for a match, so you just need to make sure that one ball has not got the explosive, you can do this by splitting the 8 balls into groups of 4, weigh 2 balls on each side for each group. The group which balances is safe...
Please note that this is not "infinite acceleration" as your topic states. It is 1g acceleration.
An infinite acceleration would get you to the speed of light instantly.
Of course, my memories are somewhat random but I can see why I would remember them in each case.
For example: Getting chased by a vacuum cleaner, my old dog biting my hand through a handpuppet, getting a question right in class that nobody else could get the answer to.
Each a rather random...
I find your observations very strange. I cannot remember a single mundane thing from my life. All my old memories are tied to emotional situations.
Very interesting. Perhaps I'm abnormal in this case. Anyone else care to comment?
I don't think you're missing anything. Your answer is correct. Except that where you said "the momentum of the canon would equal the momentum of the canonball" you should take care to note that they are in opposite direction and so momentum (a vector) is not equal, but only equal in magnitude.