On 21/7/2007 11:01 PM, Harry Veeder wrote: > Something else leaves me wondering... > >> Harry wrote: >> >>> While the brakes are applied the wheel is not turning about >>> its own centre. > > Michel wrote: >> Wrt the ground it isn't, but wrt the distant stars it is, at the >> rate of one turn per day (it can't be non-rotating wrt both, >> agreed?). > > > If you began to ride the wheel nearest the ground after the brake is > realeased the net centrifugal force you would feel should depend > only on the rotation of the earth, since the wheel is not rotating > wrt to the ground. > > However, wrt to the distant stars the wheel is rotating so you should > feel a reduced centrifugal force. > > Apparently theory leads to a contradiction. > > Or is my reasoning faulty? > > Harry >
How does this sound? The centrifugal force on the person due to the Earth's rotation with the brake on is inversely proportional to radius of the Earth. However, when the brake is off the centrifugal force is inversely proportional to the radius of the Earth PLUS the radius of the wheel. Therefore, although the path traced by the person is the same in both cases the net centrifugal force is different. It would seem the way you are connected to the Earth can affect your apparent weight. However, this dependence would disappear if the Earth were not rotating. Harry
