Related Rates on the Street

Published by patrick honner on

I feel like I’ve had this experience many times in my life:  I’m biking down the road, or walking along at a brisk pace, and out of the corner of my eye I catch a glimpse of a person I think I know.  As I turn back to take another look, a well-positioned telephone pole or lamp post gets in between me and the unknown.

Somehow, the geometry and physics of the situation perfectly conspire to always keep the pole between me and the mystery person.

Click on the image below for a demonstration

A thorough analysis of the problem would be interesting, taking into consideration the different initial velocities, the different positions, the radius of the pole, different paths, and the like.

patrick honner

Math teacher in Brooklyn, New York


Lawrence · August 3, 2010 at 2:08 pm

I didn’t know you also got hit by an elephant.
But it’s interesting how the speed your traveling and the direction your looking at still blocks your view of the person, considering that he/she is also moving.

mrhonner · August 3, 2010 at 9:58 pm

The elephant is there to remind you to always keep your eyes on the road.

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