On Wed, Jun 26, 2019, 10:17 Gregg Eshelman via Emc-users < [email protected]> wrote:
> I've read that centripetal force is "pushing inward" which sounds like > utter baloney to me. When anything is spinning, nothing is pushing inward. No, that's not right. If nothing pushed inward then the body would fly of on a tangent straight line, as Newton said. The centripetal force makes it turn inward and follow the circle. The body therefore accelerates and that is equivalent to an effective force F=m a that feels centrifugal. It's going around in a circle with every atom attempting to fly outward. If > the spinning thing is hollow and there are loose objects inside it, such as > people, those objects are being forced outward by the centrifugal force > while the material composing the outer parts and the inner surface resists > that outward force - as long as structural integrity doesn't fail. > > If a spinning object's integrity fails, the broken bits fly off at tangent > vectors which can be calculated based on rotational speed, angular > velocity, and mass of the fragments. > Force requires motion, or the energy expended *attempting* to produce > motion. In a rotating object there's no force *attempting to push or pull > inward*, it's resistance to outward motion - until the object is of > sufficient mass that gravity is strong enough to bother with. Get up to > planet size and centrifugal force and gravity get to have a spinning tug of > war that slightly flattens planets that rotate fast enough. > Earth's mass and rotation speed make the diameter at the equator enough > larger than the distance through the axis that Mt. Everest is only the 10th > highest point from Earth's center, with the peak of Mt. Chimborazo 1.3 > miles higher than the peak of Mt. Everest. > On Wednesday, June 26, 2019, 12:33:04 AM MDT, Erik Christiansen < > [email protected]> wrote: > I wasn't exposed to such overzealous physics lecturers, although > colleagues back in the '80s had been. My reaction to them describing > centrifugal force as a "fictitious force" was to reason that it is a > resultant force, equal and opposite to the centripetal force which is > continually accelerating the mass, just as gravity does with > astronomical bodies. But that's just my reaction to what I heard. > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
