B Robson wrote:
> 
> 
> Gabor Farkas wrote:
> 
>> Simon wrote:
>>> This page seems to have the answer.
>>>
>>> http://www.abc.net.au/science/k2/homework/s95523.htm
>>>
>> sorry, but this is...hmm...i wonder if he really does not know it, or 
>> he is trying to explain it using simpler terms and because of that he 
>> says something wrong....
>>
>> "
>> The suck of gravity is not as powerful as the explosive gases that 
>> push it out of the barrel. So it will accelerate to a maximum speed of 
>> not 3,000 kilometres per hour, but somewhere between 330 and 770 
>> kilometres per hour - depending upon the weight and shape of the bullet.
>> "
>>
>> ?!?!?!?!?
>>
>> what's he talking about?
>>
>> yes, the explosive gases maybe represent a greater force, but they 
>> stop affecting the bullet after it left the gun. on the other hand, 
>> the gravity affects the bullet the whole time.
>>
> 
> when the bullet leaves the muzzle it has high energy, it takes the 
> effect of drag time to decelerate the round.
> 
>> and since when does the weight of an item affect the speed of it's fall?
> 
> 
> he said "weight AND shape".
> 
>>
>> to keep this simple:
> 
> 
> it's not simple.
> 
> 
>> let's ignore the air resistance for a while.
>> if you shoot something up vertically, it will come down with EXACTLY 
>> the SAME speed as it was shot upwards.
>> but of course you cannot ignore the air resistance, and it will affect 
>> the whole equation. so the end results he gives can be correct.
>>
>> but not the bullshit about which force is greater...
>>
> 
> gravity IS a weak force watch a magnet easily support itself against 
> gravity . (It isn't actually a force but that's another story).
> 

i agree with all that you wrote here.

i'll try again to explain what i am complaining about:

the quote i quoted :) :


"
The suck of gravity is not as powerful as the explosive gases that
push it out of the barrel. So it will accelerate to a maximum speed of
not 3,000 kilometres per hour, but somewhere between 330 and 770
kilometres per hour - depending upon the weight and shape of the bullet.
"

the part i quoted is not true. the reason why the bullet does not reach 
3000km/h is not the power-difference between gravity and 
explosive-gas-power ;), but the air resistance.

that's all

gabor