Re: [Phys-L] inertia and the tablecloth demo

["Bob Sciamanda" <treborsci@verizon.net>]

Yes. Unless there is slippage, the friction involved between your shoe (or a 
tire) and the road is STATIC friction.

Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
treborsci@verizon.net
www.sciamanda.com

-----Original Message----- 
From: Anthony Lapinski
Sent: Wednesday, August 17, 2016 2:00 PM
To: Phys
Subject: Re: [Phys-L] inertia and the tablecloth demo

Surfaces in contact don't have to be moving (relative to each other) for
friction to be present. This would be static friction. I have my students
draw FBDs for 5 cases:

1. push block on level table with constant velocity

2. push block on level table but it remains at rest

3. push block against a wall

4. block at rest on incline

5. block at rest on level table

This leads to a discussion of the two types of friction. Then, how it is
measured, coefficient of friction, etc.



On Wed, Aug 17, 2016 at 1:53 PM, Bob Sciamanda <treborsci@verizon.net>
wrote:

> -----Original Message----- It was written:
>
> > Our syllabus describes frcition as  a force that opposes motion.
>
> Where's That From?????
> > >
> I ask how could we move if there was no friction?
> >
>
> Good question!  The syllabus doesn't make any sense.
> > >
> > *****************************
>
> Friction opposes the relative motion of surfaces in contact -
> it opposes slipping of your feet when you walk -
> it opposes slippage of the tires as a car accelerates.
> When motion of the contact point is thus impeded momentum is transferable
> into other, allowed motion.
>
> Bob Sciamanda
> Physics, Edinboro Univ of PA (Em)
> treborsci@verizon.net
> www.sciamanda.com
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