On 3/6/2007 12:14 AM, Horace Heffner wrote: > > On Jun 2, 2007, at 2:59 PM, Harry Veeder wrote: > >> >> According to the logic of Newton's laws of motion, the ions have to >> remain >> immobile to be able to pull the ball forward. However, the forward >> motion >> the ball will in turn be impeded by the ions immobility. >> Therefore, the ball should not move according to Newton. > > This is not so. It is only necessary that the ions be accelerated > toward the ping pong balls. Newton gives > > F = m a > > so, given a force and ion mass: > > a = F/m > > and we can calculate the ion acceleration. This acceleration means > the ions only have a fleeting existence in front of the balls. The > ions in front of the ping pong balls have to be continually > replenished to sustain a fixed force, i.e. a space charge has to be > maintained, but the radial ion wind does this replenishing. > > Regards, > > Horace Heffner >
Ah I see. But for this to account for the rotation the charge on the ping pong balls must be opposite to the space charge. Is this necessarily so? Harry
