gravity works better on heavier objects... (was swb vs. GR, etc)

[Paul Bruneau]

Tom Sherman wrote:

> Being an intelligent man, I believe Galileo Gallili would have had his assistant on the ground
> getting a close look at the cannonballs landing while he was dropping them out of the tower.
>
> Tom Sherman - Quad Cities USA (Illinois side) Various HPV's

Tom, what does your intelligence have to do with what Galileo might have done? (I love getting you
on this common grammatical error

 

[Robert Siegel]

Mark -- Are you still riding your GRR? If so, for what kind of rides? Also, how did the faired GRR
stack up against the Aero?

Gator Bob Siegel EasyRacers Ti Rush

>> Coming up on 1000 miles on the Aero and Love it.
> Mark Milam Lafayette, LA GRR, Ti Aero, Screamer

 

[Rcpinto]

>If Gallileo could have looked closely enough, the heavier cannonball (or whatever it was) would
>have hit the ground very slightly ahead of the smaller, lighter one. This is because the mass
>increases with the cube of the diameter, but the frontal area only with the square of the diameter.
>For a fairly short fall, with dense, heavy objects, the difference was too small for him to see. In
>a vacuum they would be dead even. At the other extreme, compare a falling sack of flour to
>individual single particles of flour (dust).
>

>Wind resistance is a major effect on bicycles, not one that can safely be neglected. With both
>people and cannonballs, weight increases more quickly than frontal area, and other things being
>roughly equal, heavy riders will out-coast light ones down a hill.
>
>Dave Lehnen
>

Ahh...great explanation Dave!

Rich Pinto
Bacchetta Bicycles

 

[Iambent]

> (This one from Tom S.)
>
> "When riding my RANS Rocket, I am able to out-coast a riding companion on a front faired TiGRR
> from a near stop up to about 15 mph (~25 kph), but the TiGRR gains speed more rapidly after that.
> I believe that this is due to my gross weight being about 30 lbs. (~13 1/2 kgf) greater but my
> having a greater CdA. [1]"

I think the difference here would be attributed to wind resistence. After all, you are not "falling"
in a vacuum. There are different external ballistic tables for subsonic and supersonic projectiles.

In the above case, I would imagine that the Rocket simply had less rolling resistence than the
TiGRR, but that once 15 mph was reached, the more aero faired TiGRR had the advantage, i.e., below a
certain speed, aerodynamics is inconsequential.

Doug Scott 2002 Windwrapped RANS Stratus Ridgeland, MS

 

[Tom Sherman]

IAmBent wrote:
> ... In the above case, I would imagine that the Rocket simply had less rolling resistence than the
> TiGRR, but that once 15 mph was reached, the more aero faired TiGRR had the advantage, i.e., below
> a certain speed, aerodynamics is inconsequential.

Don't say this around the "big wheels are better" crowd! My Rocket was equipped with 47-406
Avocet Freestyle tires inflated to 90/100 psi
(6.2/6.9 bar) front/rear, while the TiGRR had 28-451 IRC Roadlite and (IIRC) 32-622 Avocet Fasgrip
tires inflated to normal pressures.

I believe the real reason I gained speed more rapidly from a near stop was due to my ability to put
everything but the kitchen sink in a RANS "yellow" bag.

Tom Sherman - Quad Cities USA (Illinois side) Various HPV's