-- Put the rod into the freezer for a while. As it cools,
it contracts (gets smaller) slightly.
-- Put the cylinder into hot hot water for a while. As it heats,
it expands (gets bigger) slightly.
-- Bring the rod and the cylinder togther quickly, before the
rod has a chance to warm up or the cylinder has a chance
to cool off.
-- I bet it'll fit now.
-- But be careful . . . get the rod exactly where you want it as fast
as you can. Once both pieces come back to the same temperature,
and the rod expands a little and the cylinder contracts a little, the fit
will be so tight that you'll probably never get them apart again, or even
move the rod.
Explanation:
Without the metric system, we'd have a different International System of Units, the metric system is important because 1mm is 0.1cm, 1 cm is 0.01m, with the imperial system the conversion is tedious. The most important feature of the metric system is its base in scientific fact and repeatable standards of measurement
you would multiply 30 by 15. because its the weight times the distance.