From: Lee Corbin (lcorbin@tsoft.com)
Date: Wed Oct 16 2002 - 02:50:31 MDT
Here is how to convert from pounds to newtons (both
units of force) and from foot-pounds to joules (both
units of energy) without touching repellant slug.
Input: our familiar knowledge that one kilogram
is about the same as 2.2 pounds, and
one foot is about 12*2.45 centimeters,
or .3048 meters. (Yes, I know that this
"common" daily way of speaking conceals
great perils. Boy, do I know!)
So, from F = MA
2.20452 lbs (force) = 1kg * 9.8 nt-m/sec^2 (mass times acceleration)
Therefore 1 lb = 9.80554/2.20452 kg nt-m/sec^2
= 4.448 newtons
or, as Spike wrote, a newton is about one-quarter
pound.
Next
1 ft-lb = 1 lb * 1 ft (force times distance)
= 4.448 newtons * .3048 meters
= 1.356 newton-meters
= 1.356 joules,
so a joule is also .7374 joules, though one
doesn't want the conversion THAT WAY, because
the 1 ft-lb = 1.356 joules is the one you need
to go from the awful English units to the sane
metric ones.
I hope that this finally meets with approval
from Spike's careful eye.
Lee
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