[SDCBC] Calling all Engineers & Math Gurus

[Tom Yager]

All right, here goes some very crude numbers.  Let me first turn everything
into metric (easier for me to do calculations).  Here are some assumptions.
All mass is assumed to be a "point mass".  The center of gravity is about 44
inches from the ground or 1.11 m.  The mass is 68 kg, the speed horizontal
is 6.7 m/s.  This gives the time of fall to be 0.47 seconds.  The distance
traveled in the air (again assuming a point mass) is 3.1 m or 10 feet.  The
person will hit the ground at 8.2 m/s or 18.3 mph (15 mph horizontal and
10.5 mph vertical).  Assuming all energy is used up in friction (very big
assumption) and the coefficient of kinetic friction is 0.8, the distance
traveled would be 4.3 meters or 14 feet.

 

Keep in mind that rolling, flailing arms and legs, and broken bones would
significantly alter these calculations.  Also the coefficient of friction is
a rough estimate.  I can refine these calculations, but this is first pass.

 

Best Regards,

Tom

 

 

  _____  

From: sdcbc-bounces at bikesandiego.org [mailto:sdcbc-bounces at bikesandiego.org]
On Behalf Of Richard Duquette
Sent: Monday, February 25, 2008 8:55 PM
To: sdcbc at bikesandiego.org
Subject: [SDCBC] Calling all Engineers & Math Gurus

 

Dear List mates                                Confidential & Privileged

Im representing a fellow bicyclist who unfortunately hit a construction
timber left in the bike lane one nite.She was traveling 12-15 miles per
hour,on a gentle downward slope.She collided before she could apply her
brakes.She tried, but there wasn't enough time even tho she was using a
handlebar mounted nite rider lite.She swerved to miss one timber, when she
hit the culprit...the second timber. She weighs 150 lbs. and was wearing a
cycling jacket & tights (and helmet), when she hit the asphalt.

My questions are:

How far did she travel in the air & on the ground (in total) before coming
to rest, assuming she essentially slid to a stop. How did you calculate this
answer.? Your best estimate is fine, with the facts provided.

Regards,



Richard L. Duquette
Bicycle Injury Lawyer since 1983
Carlsbad, CA
760-730-0500
www.911law.com <http://www.911law.com/>  

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