Bullets falling back to earth
Don sez:
"Acceleration is, by definitition, rate of change of velocity with
time AKA dv/dt. If me arse is changing velocity at the moment I
sure don't notice it."
That's because you aren't (we aren't) finely tuned enough to notice the
teensy-tiny interval dv/dt. grin
Bob Swinney
"Don Foreman" wrote in message
...
On Wed, 17 Dec 2003 04:39:59 GMT, "Bob Swinney"
wrote:
Ignoring this will just confuse you.
Maybe, Ted, but *acceleration* from gravity is not diminished in any way.
At each instant, dt, acceleration is still present. The result is offset
by
the drag of the air and a sort of equilibrium seems to exist, but
acceleration from gravity is constant. Matter of fact you and I are
accelerating right now toward the center of the earth - but our movement
is
arrested by offsetting forces. Nevertheless, at any given instant, dt,
we
are accelerating.
Gravity is a force proportional to mass which makes it acceleration in
terms of math units, but that only becomes dv/dt in a force equation
after other forces like restraint ( the stool me arse is perched on)
and viscous or aerodynamic drag that impedes the descent of
snowflakes, parachutists, and other falling objects is included.
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