moment of inertia (ignore if you want)

[Stephen Birkett]

I wanted to explain with another analogy because I think it's
important to understand the concept and it's relation to hammer
actions. I'm sure everyone has tried the following experiment: take
a (woodworking) hammer and knock in a nail holding the hammer near
the head, then, with the same hammer, knock in a nail holding the
hammer at the end of the grip. You can feel the difference...the
*only* thing changed is the moment of inertia (increased in the second
example). The hammer is harder on the wrist but the nail goes in a
damn sight faster. In both cases, however, the hammer mass is
identical and would give precisely the same strike weight value.
That's the difference between static (mass) and dynamic (moment of
inertia).

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