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Re: Some More Problems




Herb Schulz <herbs@INTERACCESS.COM> writes:


1) Imagine a tricycle wheel (direct drive through the pedals) with the
pedals vertical which is free to roll without slipping. Apply a
constant force to the BOTTOM pedal (to the right in this example). The
force
is NOT large enough to cause the wheel to slip over then surface. What
is
the direction of acceleration of the wheel (and why!)?

If the pedals are vertical, applying a vertical force to either the top
or the
bottom pedal will not result in a forward motion or backward motion
of the tricycle. In this case the acceleration would be g (in the
vertical
direction)

If the force applied to the bottom pedal is mostly downward (with both
horizontal and vertical components) the acceleration of the tricycle
would be
partly in the backward direction and partly g. In addition, because the
bottom
pedal is a bit to the right of the tricycle center of mass, it would
create a torque
that would produce a centripedal acceleration as well.

Herb Gottlieb from New York City
(Where our physics texts do not include tricycles problems, only
bicycles))

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