S
Seth Jayson
Guest
Saw comments like this a few times in the long thread regarding rolldowns and coasting:
(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]"
Now, last time I checked, gravity, even when diluted by, say, a hill, pulls objects with the same
accelleration, no matter what their mass. (Remember Gallileo and his different orbs dropping from
the window of the Church in Pisa?)
Now, I remember back when building pinewood derby racers that we all seemed to think heavier was
better too.
Why this assumption? It seems to be pretty common
Given the same equipment, running in a vaccuum, two bikes carrying different masses ought to have
the same acceleration down the same slope.
In the real world, where there's wind resistance, etc., do we start to see some advantage from
greater mass in keeping our momentum against the wind?
sj
(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]"
Now, last time I checked, gravity, even when diluted by, say, a hill, pulls objects with the same
accelleration, no matter what their mass. (Remember Gallileo and his different orbs dropping from
the window of the Church in Pisa?)
Now, I remember back when building pinewood derby racers that we all seemed to think heavier was
better too.
Why this assumption? It seems to be pretty common
Given the same equipment, running in a vaccuum, two bikes carrying different masses ought to have
the same acceleration down the same slope.
In the real world, where there's wind resistance, etc., do we start to see some advantage from
greater mass in keeping our momentum against the wind?
sj