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Re: Car acceleration

Gary Turner wrote:
. . .
Now, is that sufficient? Is the car going to move? I have relied on
static friction only here and the end result is that the force is
between
the engine and tires.

Analyses of the internal forces between (or among) the internal parts of a
system (the car or the skater) will illuminate the mechanism whereby the
increased kinetic energy of certain system parts (tires; skater's arm) is
generated. This kinetic energy is internal to the system and will not
directly change the system (CM) momentum - as happens on ice, where much
KE is generated but no CM acceleration. These moving parts must then be
used (through mechanisms of friction, rigidity, etc) to elicit a force
from an external object in order to produce a momentum exchange between
the system and the external world.

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor