OT: Speed of light

[Hrvoje Niksic]

Jeff Schwab <jeff at schwabcenter.com> writes:

> Jeroen Ruigrok van der Werven wrote:
>> -On [20080212 22:15], Dotan Cohen (dotancohen at gmail.com) wrote:
>>> Note that Google will give a calculator result for "1 kilogram in
>>> pounds", but not for "1 kilogram in inches". I wonder why not? After
>>> all, both are conversions of incompatible measurements, ie, they
>>> measure different things.
>>
>> Eh? Last I checked both pound and kilogram are units of mass, so where is
>> the incompatibility?
>
> I've never heard of "pound" as a unit of mass.  At least where I went
> to school (Boston, MA), "pound" is the English unit of force, "slug"
> is the (rarely used) English unit of mass, and "kilogram" is the SI
> unit of mass.

It would be possible for US pound to only refer to weight, but I
cannot find references to corroborate it.  For example, taken from
Wikipedia:

    In 1958 the United States and countries of the Commonwealth of
    Nations agreed upon common definitions for the pound and the
    yard. The international avoirdupois pound was defined as exactly
    453.59237 grams.

The "pound-force" wikipedia entry documents "pound" being used as a
unit of force "in some contexts, such as structural engineering
applications."