On 25/7/2007 2:01 PM, Harry Veeder wrote: > 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.
oops, that should be directly proportional to the radius of the Earth, (if the earth's rotation is constant). > However, when the brake is off the centrifugal force is inversely > proportional to the radius of the Earth PLUS the radius of the wheel. also directly proportional to the radius of Earth plus radius of 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 > Harry
