From: Steven Eiger (eiger@montana.edu)
Date: Wed Jan 26 2000 - 13:33:56 PST
Message-Id: <l03102800b4b515ca6606@[153.90.241.107]> Date: Wed, 26 Jan 2000 14:33:56 -0700 From: Steven Eiger <eiger@montana.edu> Subject: Re: pinhole friction with tires
Sarah,
When you hit the brakes hard, locking up the wheels, they slide over the
road. This is kinetic friction. It is like sliding a block across the
table. It usually requires a larger force to get the block moving
initially, this is static friction, the force holding the block or wheel
static tot he surface. Rolling friction is different from these two as the
wheel is statically adhering to the road, yet as it rolls it deforms, this
deformation degrades energy. The earlier answer implied that deformable
objects are easier to slide than roll. obviously this is very dependent on
the vlaue of kinetic friction and the rolling resistance. For a tire, even
on a gym floor, it is much easier to roll it than to drag it. Of course,
it does not deform nearly as much as a rolled up gym mat as they both roll.
eiger
>So from Heidi's answer I see that other people do teach the concept of
>rolling friction. Is rolling friction distinct from static friction though?
>I'm still confused. Sarah
>
>İİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİİ
>
>Sarah Wise
>
>Lick-Wilmerding H.S.
>755 Ocean Avenue
>San Francisco, CA 94112
>swise@lick.pvt.k12.ca.us
>
>"Not everything that can be counted counts,
>and not everything that counts can be counted."
>--Albert Einstein
>
>
>
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Steven Eiger, Ph.D.
Departments of Biology and the WWAMI Medical Education Program
Montana State University - Bozeman
Bozeman, MT 59717-3460
Voice: (406) 994-5672
E-mail: eiger@montana.edu
FAX: (406) 994-3190
This archive was generated by hypermail 2b29 : Thu Oct 19 2000 - 11:10:28 PDT