Hauling, Rod-loading.

rb608 wrote:
On Nov 10, 6:22 am, wrote:
Some considerations on casting and rod loading.

A simple calculation for casting in air is;

Frt = Fi * Fa * Ff * Flt

Where Frt = the force on the rod tip in kg.m/s², Fi = inertia (mass)
in grams, Ff = the coefficient of fluid kinetic friction µk ( air
resistance), Fa = the acceleration of the line in ms², and Flt = line
tension in kg.m/s²


Now, I admittedly can't haul worth a ****, but I do know my physics
(maybe that's my problem.) I'm having a bit of difficulty reconciling
your theory above with that of Mr. Newton who opined a much simpler
equation, F=ma.

Force equals mass times acceleration. That's it.

The extra terms you included (Ff and Flt) are misplaced IMO. Under no
circumstances would they be multiplication terms in the equation. The
line tension is just another Force that would be part of the net force
on the tip of the rod, not a separate term.

The air resistance term (what units are you thinking for that one?)
also does not belong there. Any resisting forces due to fluid
friction would similarly be a part of the net value of the Force at
the rod tip. It does not belong in the equation as a multiplicative
term.

As I said, I can't haul; but I fear the inaccuracies of your
mathematical equation may be detracting from your practical
instruction.

Line tension is a "special" force, considered to be parallel to the
string under tension. However, as the line acceleration is dependent on
this tension, it must be proportional to it.

The force on the rof tip, and the force on the end of the line are
"normal" forces and can be measured directly.

Friction and line tension both affect the acceleration of the line when
it is moving, and have to be included in the dynamic equation.

For a static system they can be ignored.