From: utzoo!decvax!decwrl!sun!megatest!fortune!hpda!hplabs!sri-unix!Schauble.HIS_Guest@MIT-MULTICS
Newsgroups: net.physics
Title: Re: Screwdriver Mystery
Article-I.D.: sri-arpa.911
Posted: Wed Apr 13 20:09:00 1983
Received: Sun Apr 17 02:53:27 1983

The screwdriver will jump out of the slot when the ANGLE it makes with
the screw exceeds a critical value. Your hand has an uncertainty in
positioning the handle of the screwdriver. The longer the shaft, the
greater this uncertainty (in inches) can be before you exceed the
critical angle. This allows you more freedom to move your hand about as
you apply force.

          Paul