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Centripetal Force

bkeats

Plastic
Joined
Apr 22, 2012
Location
Sydney, Australia
Hi All,
Can someone tell me what Centripetal Force means? I saw it recently used in conjunction with the operation of a lathe chuck.

Cheers,
Brent
 

Red James

Stainless
Joined
Jan 26, 2013
Location
Plainfield, Indiana, USA
Hi All,
Can someone tell me what Centripetal Force means? I saw it recently used in conjunction with the operation of a lathe chuck.

Cheers,
Brent
Centripetal Force is the force required to exactly balance the Centrifugal force created by rotating an object around a center point. A moon is forced into a "circular" path around a planet by centripetal force from gravity ... balanced by the centrifugal force of rotating around the planet. Centripetal means "center directed". It is common to describe the rock on a string whirling around as being confined by centrifugal force, but it is really centripetal force. The centrifugal force is what pushed the rock out against the string.

The spinning lathe chuck jaws are pushed outward with centrifugal force. The scroll of the chuck applies the centripetal force to keep the jaws from flying out. This concept is more confusing than it is worth. . . just say centrifugal force and everyone knows what you mean.
 

angelw

Diamond
Joined
Sep 10, 2010
Location
Victoria Australia
The spinning lathe chuck jaws are pushed outward with centrifugal force. The scroll of the chuck applies the centripetal force to keep the jaws from flying out. This concept is more confusing than it is worth. . . just say centrifugal force and everyone knows what you mean.

Hi Red,
The so called Centrifugal Force, is not an actual force, but implied at best. With the Rock and String example, its true that the string exerts the Centre Seeking (Centripetal) force on the rock. At the moment the string breaks, the rock leaves the circular path in a dead straight line, tangent to the circular path being forced upon it. Accordingly, its inertia that rules the path once the Centripetal force is removed. Centrifugal Force could be defined as Zero Centripetal Force.

The chuck jaws are wanting to travel in a straight path. There is no force making the jaws deviate from this straight path away from chuck centre (Centre Fleeing as is the literal meaning of Centrifugal).

Regards,

Bill
 

706jim

Stainless
Joined
Jun 14, 2006
Location
Thunder Bay Canada
More spcifically, it refers to the tendency of hydraulic chucks to open up at high rpm's as their gripping force is reduced by centrifugal (or centripital) force.
 

angelw

Diamond
Joined
Sep 10, 2010
Location
Victoria Australia
CentriFugal flings things outward.
CentriPetal pulls things inward.

Except there is no outward flinging going on.

If you were sitting in a car, on the seat, and the vehicle accelerated in a straight path forward, you would be pressed against the back of the seat. But there's no force pushing you towards the back, it's just your inertia resisting the back of the seat pushing towards you. And that's all "centrifugal force" is - when the vehicle is cornering, the passenger feel as though they are being flung outward - but there's no force flinging the passengers in an outward direction at all. Its Centripetal force being provided by the friction between the vehicle tires and road, and in turn, between passenger and seat, or passenger restraint by seat belt, or the push of the door against the passenger. In all cases, the passenger wants to keep moving in a straight direction, tangent to the circular path being forced upon the vehicle and passengers. The feeling of being flung outward is just the passenger's inertia resisting the Centripetal force being applied.

Regards,

Bill
 

sfriedberg

Diamond
Joined
Oct 14, 2010
Location
Oregon, USA
My posting was intended as a short mnemonic aid, not a freshman physics lecture on inertia and acceleration. Thank you for providing same.
 

angelw

Diamond
Joined
Sep 10, 2010
Location
Victoria Australia
My posting was intended as a short mnemonic aid, not a freshman physics lecture on inertia and acceleration. Thank you for providing same.

Well then, it could more accurately be:
CentriFugal is a fictitious force, as its referred to, not an applied force.

Regards,

Bill
 
Last edited:

sfriedberg

Diamond
Joined
Oct 14, 2010
Location
Oregon, USA
Bill, I don't intend to get into a pissing contest, but you need to think about rotating frames of reference before calling centrifugal forces fictitious.
 

HuFlungDung

Diamond
Joined
Jan 19, 2005
Location
Canada
Why are people so cowardly about pissing contests, anyways? If no one ever wants to get into a pissing contest, someone, somewhere, at sometime, most certainly did want to get into a pissing contest, and hence, he proposed it :D
 

CalG

Diamond
Joined
Dec 30, 2008
Location
Vt USA
Bill, I don't intend to get into a pissing contest, but you need to think about rotating frames of reference before calling centrifugal forces fictitious.

Frames of reference be damned. Inertia defines the path, real forces act to modify the path

There is NO single FORCE that causes an object to describe a curved path. ( Unless you wish to get into theoretical aspects of "curved space" )

perhaps centrifugal could be defines as a sumation effect. But it is not a "force".

It is a term in common use however, so perhaps that too will change.
 

angelw

Diamond
Joined
Sep 10, 2010
Location
Victoria Australia
Bill, I don't intend to get into a pissing contest, but you need to think about rotating frames of reference before calling centrifugal forces fictitious.
Yes, I understand that, and I'm not the instigator of "fictitious" with regards to Centrifugal force; it is what it is.

I understand that in a rotating frame of reference the objects appears to accelerate away from the center of rotation. However, the centrifugal force is really an inertial force, meaning that it is caused by the motion of the frame of reference itself and not by any external force. Centripetal force is a real force independent of the frame of the observer.

Regards,

Bill
 

Heavey Metal

Banned
Joined
May 10, 2011
Location
Texas
What dum as put tires and a seat on your chuck?

The observed force wanting to open your chuck jaws is ?

''Centrifugal Force could be defined as Zero Centripetal Force''. So what the fuck is holding your chuck jaws on did you forget the bolts?
Except there is no outward flinging going on.

If you were sitting in a car, on the seat, and the vehicle accelerated in a straight path forward, you would be pressed against the back of the seat. But there's no force pushing you towards the back, it's just your inertia resisting the back of the seat pushing towards you. And that's all "centrifugal force" is - when the vehicle is cornering, the passenger feel as though they are being flung outward - but there's no force flinging the passengers in an outward direction at all. Its Centripetal force being provided by the friction between the vehicle tires and road, and in turn, between passenger and seat, or passenger restraint by seat belt, or the push of the door against the passenger. In all cases, the passenger wants to keep moving in a straight direction, tangent to the circular path being forced upon the vehicle and passengers. The feeling of being flung outward is just the passenger's inertia resisting the Centripetal force being applied.

Regards,

Bill
 

Heavey Metal

Banned
Joined
May 10, 2011
Location
Texas
Was that you or your evil twin that said this

"Centrifugal Force could be defined as Zero Centripetal Force"

How do you machine an analogy (do you have a print that you can share?)

1. Its called an analogy.
2. Inertia.
3. Centripetal Force.
 








 
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