Everyday Uses of Conics

Date: 05/24/99 at 12:37:43
From: Holly
Subject: Everyday uses of Conics

I have a project coming up in which I am supposed to construct a model 
of a commonly used object in the shape of a conic. I would like to 
know if there are any interesting everyday uses for parabolas, 
ellipses, or hyperbolas. I know of a few, like a spoon, a bridge, a 
football, and maybe an egg, but I think almost everyone in my class 
has those very same ideas. I have searched your pages, other Web 
sites, and books on conics, and have not found anything that could 
help me. I would appreciate it very much if you could assist me with 
some ideas.

Thanks,
Holly.

Date: 05/25/99 at 23:41:47
From: Doctor Tom
Subject: Re: Everyday uses of Conics

Hi Holly,

If you have a light in a lampshade, the shape of the shadow on a flat 
wall is a hyperbola.

If you have a planet going around a sun, the shape of the orbit is an 
ellipse. If it's a comet that's going to escape from the solar system, 
it's a hyperbola.

The reflectors in car headlights are parabolas rotated around so that 
the light from the bulb (at the focus of the parabola) will all be 
directed straight out from the car.

Any circle looks like an ellipse when viewed at an angle.

I hope this helps.

- Doctor Tom, The Math Forum
  http://mathforum.org/dr.math/