Re: [Phys-l] racing

[Paul Nord <Paul.Nord@valpo.edu>]

Another little known fact:

Indy cars have a much HIGHER drag coefficient than passenger cars.  They use the air to push them down and keep them on the track.

Paul


On Oct 25, 2011, at 3:39 PM, Quist, Oren wrote:

> A little known fact, that I think is true !!
>
> Cars go around most (all?) race tracks in a counter-clockwise direction.
>
> The engine, laying horizontally, rotates so that the angular momentum vector is in the forward direction.
>
> Turn the car to the left (counter-clockwise) puts a torque on the car producing a downward force on the front wheels -- helps traction as the car turns.
>
> Turn the car to the right -- front end tends to lift up for the same reason.
>
> Do I have my directions right???
>
> ________________________________________
> From: phys-l-bounces@carnot.physics.buffalo.edu [phys-l-bounces@carnot.physics.buffalo.edu] on behalf of brian whatcott [betwys1@sbcglobal.net]
> Sent: Tuesday, October 25, 2011 2:26 PM
> To: phys-l@carnot.physics.buffalo.edu
> Subject: Re: [Phys-l] racing
>
> On 10/25/2011 1:15 PM, Anthony Lapinski wrote:
> > I'm teaching about friction now and a discussion came up about race cars.
> > I mentioned that these cars usually have a spoiler on the back end so that
> > air pushes down on the fast car, which increases the apparent weight,
> > which increases the frictional force. This is good as it makes the car
> > accelerate more on straight track and more stable on turns
> >
> > Kids mentioned that race cars can "flip over" if they go too fast. My
> > question is how does a race car flip over going fast on a long stretch of
> > straight track.? Ignoring the spoiler, aren't these cars designed so that
> > they will grip the road better due to the aerodynamics? Or do most cars
> > become airborne due to interactions with other cars or air currents on the
> > track?
> >
> > _______________________________________________
> > Forum for Physics Educators
> > Phys-l@carnot.physics.buffalo.edu
> > https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l
> Things that are basically flat underneath and curved on top, or where
> the airspeed
> runs much faster above than below, con develop lift.    If they were
> shaped like a
> low drag wing section, the lift would tend to rotate the shape nose up,
> which is
>  an unstable circumstance. You will recall that most wings proceed from
>  zero lift to maximal lift in about 15 degrees of rotation - so it
> doesn't take
> much of a pitch upset to trigger an instability. For a wedge-shaped object,
> the variation of lift with pitch might proceed differently, and this is
> one way
>  to think about surfaces intended to progressively push down harder with
>  increasing speed.
>
> Brian W
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