Helmet fire, I hope I have time to cover this.
I actually agree with step 13 in the logic thread, but step 14 is where I disagree. It's interesting that both Lu and Nick are missing it at exactly the same point, which is blending (or merging) 2 separate forces together. They are blending the centripetal force with an acceleration force.
Let me try it this way by covering your rollerskate and V8 RV example, but I'd like to change the RV to a van with no seats (except the driver's) and a flat floor, so the rollerskates can work.
Suppose the van were stopped on a road with a driver inside and you were standing outside the van on the road next to the driver's window, with the rollerskates on. Then suddenly the driver hit the gas and accelearated the van down the road. The van would now be in motion, but you would be left standing on the road in the same spot, since the state of your motion would not have been changed by the acceleration of the van.
Now suppose you are inside the van (instead of being outside) next to the driver with the rollerskates on. Again the driver suddenly accelerates the van. At first, due to the vastly reduced friction between yourself and the floor of the van (caused by the rollerskates), you will remain in the same spot (over the road) since no acceleration force has been applied to you yet. In other words your "inertia" or momentum has not changed without acceleration.
But this will last only briefly until the back of the van accelerates to the same spot over the road that you occupy. Then you'll be accelerated in a very abrupt manner as the back doors apply the acceleration force to your body that the floor could not, because of the rollerskates.
Now here's where Lu and Nick are missing it...gosh, I just ran out of time. Bad timing, I have to get back later.
[ 17 December 2001: Message edited by: Flight Safety ]