Merlin wrote:OK, so my last comments in this thread: a rod can start unloading before the end of acceleration, it is a matter of a few 1/100 seconds and nobody cares but me.
Merlin -
F=ma
In this case the F can be measured by the bend in the rod....
Hal,
this is not correct! There is not a one-to-one relation between the acceleration of the rod handle...
I think it is correct. As long as the a and m are the line's figures.
The bend may not be bigger for higher force as it depends on the rod angle.
I'm here just for the chicks.
President of The Village Idiots of Vantaa Rapids
President of The Casting Federation of Finland
No the energy input is not the same. That is the whole point; the spring effect of a bendy rod allows you to input more energy for the same acceleration/speed-profile than a rigid lever.
work = force * distance
The distance the two rod tips travel while the input force is acting, (i.e. the distance the tips travelled during the acceleration phase at the butt) is longer for the flexible rod. So the constant force has been applied over a longer distance and for the flexible rod has done proportionally more work.
Kinetic Energy = 0.5*mass* velocity^2
Provided that the spring stiffness/mass combination results in an increase in velocity, there is also a proportional increase in kinetic energy.
