From: utzoo!decvax!yale-com!leichter
Newsgroups: net.physics
Title: Re: Screwdriver Mystery
Article-I.D.: yale-com.1280
Posted: Wed Apr 13 09:47:07 1983
Received: Fri Apr 15 01:57:50 1983
References: houxq.360

You know, I never thought about it before - but I've known for years that you
should use a long screwdriver when trying to drive a screw hard.  Here's a
simple theory:

It's difficult - impossible, in fact - to avoid placing some sideways force
on the screwdriver handle as you use it.  This causes the screwdriver to
rotate about its point of support, i.e. the point at which it touches the
screw head.  If it rotates too far, some side or the other of the blade will
slip out of the slot in the head and the screwdriver will slip.  Now, for
the same lateral movement of the screwdriver handle, the induced movement of
the head is smaller for a longer screwdriver (since the motion induced is a
rotation, and the angle the screwdriver moves through is smaller when a fixed
lateral movement occurs further from the point about which rotation takes
place).
							-- Jerry
						decvax!yale-comix!leichter
							leichter@yale

BTW:  Psychologically, it FEELS as if you can actually turn harder when the
handle is long.  I think this is just a matter of automatic reactions trying
to keep the screwdriver under control, and causing you to loosen up when it
starts getting out of control.		-- J