I made a drawing of the situation I was imagining: http://web.ncf.ca/eo200/world-ferriswheel.html
A ferris wheel located on Earth's equator. Initially a brake prevents the wheel from turning. After the brake is released and assuming the axel of the wheel is frictionless, will the orientation of the wheel remain unchanged as the Earth revolves? Harry On 20/7/2007 5:42 AM, Michel Jullian wrote: > Lets' assume the wheel axis is parallel to the Earth's for simplicity. Moving > the hub around in the plane of the wheel shouldn't change its rate of rotation > wrt an inertial frame if there is no friction. > > If it's initially non-rotating wrt the distant stars (i.e. rotating once per > day wrt the Earth) it will remain so, you can verify that with a bicycle, lift > the front you'll see that the front wheel keeps the same orientation. > > If it's initially non-rotating wrt the Earth, i.e. rotating once per day wrt > the distant stars, it will keep its angular speed i.e. it will remain at rest > wrt the Earth. > > Michel > > ----- Original Message ----- > From: "Harry Veeder" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Friday, July 20, 2007 5:23 AM > Subject: Re: [Vo]:centripetal force question > > >> >> Imagine a ferris wheel (absent the carriages for simplicity) which is >> initially at rest. >> >> As the world turns, the ferris wheel will complete one revolution in a day >> (assuming no friction) with respect to an observer standing >> beside it. >> >> Yes? No? ...or? >> >> Harry >> >> >> >> >> On 15/7/2007 5:17 PM, Michel Jullian wrote: >> >>> Hi Thomas, >>> >>> The (fictitious, or apparent) force you're talking about is a function of >>> _rotations_ (not revolutions) per second, and also of your mass and of your >>> distance from the axis >>> (force=mass*(2*pi*rotations_per_second)^2*radius_of_the_earth assuming you >>> stand on the equator), nothing to do with distance traveled by the planet, >>> and >>> it is not centripetal (going towards the center) but centrifugal (think of >>> fugitive = going away from the center), if it was centripetal it would not >>> subtract from but add to actual weight, which is the actual centripetal >>> force. >>> >>> Michel >>> >>> ----- Original Message ----- >>> From: "thomas malloy" <[EMAIL PROTECTED]> >>> To: <[email protected]> >>> Sent: Sunday, July 15, 2007 10:02 PM >>> Subject: [Vo]:centripital force question >>> >>> >>>> I'm subject to weight loss produced by the centripital force produced by >>>> the earth's rotation, I'm wondering if centripetal force is a function >>>> of revolutions per time unit, or total distance traveled as the planet >>>> travels? >>>> >>>> >>>> --- http://USFamily.Net/dialup.html - $8.25/mo! -- >>>> http://www.usfamily.net/dsl.html - $19.99/mo! --- >>>> >>> >> >
