Re: The drag force -- a correction squared

[Brian McInnes <bmcinnes@PNC.COM.AU>]

Justin has given us the full transcript

> "As the simplest example of the resisted motion of a particle, find the
> displacement and velocity of horizontal motion in a medium in which the
> retarding force is proportional to the velocity.....the Newtonian equation
> F=ma provides us with the equation of motion
>
> ma = m (dv/dt) = -kmv    where kmv is the magnitude of the resisting force
(k equals constant) ...."

(1) ma = -kmv  is not wrong.

(2) neither is mv  =  -km(mu)(rho)(moment of inertia)(any other
irrelevant constant you like).

(3) ma = -kv  is better.

(4)if the idea of inserting m among the constants on the RHS is to
eliminate the explicit appearance of mass in the differential equation
of motion, it has the unfortunate consequence of implying that there
is no such explicit dependence of the motion on mass.

Brian McInnes