Re: [Phys-l] Centrifugal redux; muddied

[Steve Highland <shighlan@uslink.net>]

But the rope IS held taut by a real force exerted outward (centrifugally) on
the end away from the center by whatever the rope is tied to that's whirling
around in a circle.  The rope pulls inward on the massive object, and the
massive object pulls outward on the rope.

The thing that isn't there is a force pulling outward on the massive object
itself.

Steve Highland
Duluth MN



> If students are still convinced that there is a centrifugal force somewhere
> ("Hey, the rope really is being held taut by *something*"), then _perhaps_
> having them think about the same situation (massive object tied to the end of
> a rope, the other end of the rope being held by some prime mover) for the case
> of uniform linear acceleration might help. Car (or spaceship, if gravity gets
> in the way) accelerates in a straight line, with something (can; astronaut)
> tied to its bumper. Rope is actually held taut by the inertia of the object
> (or by N3, if one reasons that way),


> but in no way is there a force tugging
> the rope in the opposite direction of movement from the car (or spaceship).

 It 
> is the car (or spaceship) wanting to get away from the _object_.