top speed

[Guest]

and - uh - sorry everybody - where's that extension ladder?

Welcome to ground level.

 

[Keapon Laffin]

Don't tell me, tell the guy in the hole.

Yeah, I just inserted it here for all to see. I didn't intend for it to be
directed at you.

The acceleration is the same initially (g) until the objects have achieved
enough velocity to create enough drag to make any difference. It is also
the same eventually (zero) when both objects achieve terminal velocity.
Terminal velocity of a lead ball is a little more than double that of a
similar aluminium ball.

Yes, you are correct. It was vastly simplified to show the concept.

 

[Keapon Laffin]

Wow! Thanx Keapon. I stand corrected, that's a fairly big difference.(I am
a victim of public schools). Would 1 Newton be a fair force for an object
falling in the lower atmosphere that had a drag coefficient of about .4 ?

That would depend on the cross-sectional area. 1N is fairly small, I mostly
used that number because it makes the math simple. Calculating the real drag
on an object takes a bit more work and would just cloud over the rest of
what I was trying to show.

 

[k. ote]

Then I guess the question to ask would be do those "wings" at the back
of the STI add any downforce to stabilize it at that speed?

Quite a bit, in terms of what I can feel. I traded up from a normal WRX and
the difference at speed is palpable. The stiffer suspension helps the feel
at high speed too.

My problem is crosswind that blows across the road side to side. Not much
that can be done about that, no matter what car you drive.

 

[k. ote]

Some individuals have reported driving at high
speeds with the trunk deliberately left
unlatched, and that it's still unlatched after
the drive.

Have you ever tried to close the trunk of an STi? I'm not surprised it was
still unlatched.

 

[k. ote]

OK - please tell me then the difference in arrival times of a metal
spehere of aluminum and a sphere of lead if dropped simultanoeusly from
- say - 100ft. assuming no cross winds and precisely the same surface
finish/COD (drag coefficient).

Carl

But you said they'd fall at the same rate, and since we're talking about
terminal velocity here, I hardly think a 100 ft drop would be
representative.

 

[k. ote]

^^^^^

Drag... Drag, not draft!
What was I thinking?

I knew what you meant. Playing silly pedantic games is not something I'd
visit on you.

 

[k. ote]

I thought we started with a subaru filled with water or with lead?
Anyway - I can see where IF drag equals weight you have an equilibrium
state. Probably need to figure the Reynolds number in too.

No, we started from an STi filled with air, and one filled with water or
lead, and I missed the word "dropped".

 

[k. ote]

That would depend on the cross-sectional area. 1N is fairly small, I
mostly used that number because it makes the math simple. Calculating the
real drag on an object takes a bit more work and would just cloud over the
rest of what I was trying to show.

Especially if we were considering a tumbling STi. *shudder*

 

[Carl 1 Lucky Texan]

Yeah, and I doubt Galileo was working anywhere near TV with the stuff he
had. I realize now he was mostly trying to DISprove Aristotle and wasn't
really equipped to do much more (using a water clock).

So, I guess the ratio of drag (from form,texture,etc. together) to mass
is what determines the TV as well as how quickly it is achieved?(all
else equal)
Thanx for clearing up my misconception.

Carl

 

[Keapon Laffin]

Especially if we were considering a tumbling STi. *shudder*

That would be well beyond my calc/physics skills. ;-)

 

[Yousuf Khan]

Some individuals have reported driving at high
speeds with the trunk deliberately left
unlatched, and that it's still unlatched after
the drive.

What would've been really impressive in that case would be if the trunk
got latched after the drive, due to the downforce of the wing.

Yousuf Khan

 

[CompUser]

@l41g2000cwc.googlegroups.com>, (e-mail address removed)
says...

What would've been really impressive in that case would be if the trunk
got latched after the drive, due to the downforce of the wing.

Right! The couple of guys that posted that
result were looking to see if it would latch,
from the downforce...it didn't <shrugs>.