# Parabolic equation of a bridge

• March 29th 2010, 03:14 AM
RAz
Parabolic equation of a bridge
Just want to make sure I'm on the right track.

I'm using $y=ax^2$ where a<0 for the bridge.

Data (arbitrary units):
Height 90
Length 500

$90=a(\frac{500}{2})^2$

$-a=0.00144$

$\therefore y=-(0.00144)x^2$

Or is there a better way of doing this?
• March 29th 2010, 04:07 AM
sa-ri-ga-ma