if you're in free fall is your terminal velocity determined by how big you are or by how much you weigh?


AND


if you went 'woooooooooooooooooooooooooooooooooohoooo' on the way down and then increased speed to faster than the speed of sound (say by shaving your head for streamlining) and THEN pulled your parachute would you hear it again as the sound fell past you?


the whole 'school' thing didn't answer nearly half my questions

Hon, I feel for Ur teachers...

*pats lil Light gently on the head and passes him a chocolate biscuit*

you on drugs!!!!!!

1) I suspect that the air resistance would be the biggest slowing factor, so probably how big you are rather than how heavy you are determines your velocity.

2) The sound wouldn't fall, it is a wave and has no mass - it would just travel in all directions for a while before losing all its' energy and fading away - probably a long time before it reached the lower position of you with your parachute released.

Disclaimer: I was never very good at physics.

I suggest that there are a few books you may want to read:

Bill Bryson's A short History of Nearly Everything

and the series of books by Terry Prattchet called Science of the discworld.

They rather nicely explain that a lot of what we were taught in school was "lies told to children"

I believe i can fly...

hmmm...... biscuit
*hungrily eats it and looks up for another*


so.... now I need to know

1. Are there drugs that make you fall faster?
2. If waves are massless why do they knock you over when you're standing too close?
3. Terry Prattchet... well nuff said - the guys a genius, quite possible already lives in the 8th dimension and only pops into this one to drop another book off with his publisher before going back to tinker with the nature of time and trees in forests - not a question I know
4. If when you're riding along you go over a stone how does it ever get thrown infront of you? If you're going say 100.... then you're wheel is only going 100, so the stone can surely only be thrown at 100mph.... so how does it end up in front of you... what gave it that 'extra kick'?

Lightrunner wrote:

1. Are there drugs that make you fall faster?

No.

Lightrunner wrote:

2. If waves are massless why do they knock you over when you're standing too close?

The waves themselves are massless but the material they are in isn't. The water or air in a wave will knock you over if you stand too close, not the wave itself.

Lightrunner wrote:

3. Terry Prattchet... well nuff said - the guys a genius, quite possible already lives in the 8th dimension and only pops into this one to drop another book off with his publisher before going back to tinker with the nature of time and trees in forests - not a question I know

Eh??

He's good, but his books are a little too short for my liking. Small print FTW!

I also quite like Robert Rankin, but he's a bit more... surreal.

Lightrunner wrote:

4. If when you're riding along you go over a stone how does it ever get thrown infront of you? If you're going say 100.... then you're wheel is only going 100, so the stone can surely only be thrown at 100mph.... so how does it end up in front of you... what gave it that 'extra kick'?

I think the friction of your tyre touching it makes it stick a little bit to your tyre, so it is spun round and flung out the top. The mudguard probably helps direct it.

The Brentwood Triangle is certainly... I personally think Surreal is a bit too normal a word

The other thing with the wheel / tyre - your tyre may not be "going around at 100 mph" due to the circumference - a smaller wheel will rotate faster to make x speed than a larger wheel. Consider this: A push bike crank does not have to rotate at 30 mph to drive the the bike to 30 mph due to gearing etc.

The trick with Terry Pratchett is that his stuff is funny on so many levels - your basic childish sense of humour is tickled - then various parts get a nudge due to the wide topic mass for his digs and doffed cap. For example - I only realised the funny side of a book of his called Mort after going to Switzerland and noticing a place with MORT on it... my french speaking friend explained that Mort = Death. The book Mort is about a bloke called Mort who becomes Death's apprentice.

alright geniuses!

Don't try and spin my crank though - so what's the mass of air?
Do I need to squeeze my luggage a lil to make sure I'm under the weight limit at the airport :S

Neither of you have answered the tyre question though.... if the bike's moving forward at 100mph then the tyre's moving backwards at the same speed SURELY!!! I'm not wheel spinning at that speed, I know the crank and big end and all the other gubbings are going at different speeds but where the rubber hits the road it must be going at same speed as me... or are we starting to get to the bottom of why I keep chewing up tyres?
I'd have thought the maximum speed that could be imparted to an object in contact with the tyre would be 100mph?
(be honest now.... even if you've not been eating mushrooms you're a lil confused right ..... welcome to my world )

Bike and tyre... it's quite possible that the stone is lodged into the tread on the tyre and it reaches escape velocity (and the correct G-force) when finally at the "top" of the wheel's spin. Therefore as the stone has less mass than the bike and yourself *grin* the "speed" that it gets thrown forward at, is "more" relative to the speed that you are traveling.

As for the mass of "air" tricky one - where are you packing your case, sea level or at the summit of Mt. Everest? At sea level the mass of "air" is 1.3g/l of course this also depends on the room temperature at the time.

*edit - added about room temp*

Oh I think you're onto something there Lutze... the force requred to push the bike forwards at 100mph, if transferred to the stone (which I may conceed weighs a fraction less than my current fighting weight), would allow the stone to travel a lot faster.

coolio