Can a uniform ring keep on rotating if rotating if no force act on it.shouldn't it stop down eventually??????

Question

plz read this before answering

take a rigid,uniform ring.now put some force on it to rotate it.now by some arrangement remove all the external forces from its vicinity.

now if U see the ring it will be rotating and each of its particle is undergoing a circular motion.

----who is providing the 'centripetal force' to particle now?.and
----shouldnt the ring eventually stop without any external force?.
(i assumed a complete inertial frame of reference)

please explain in detail.

I think I failed to explain my question.I asked that ring is accelerating (since it is moving in a circle).but it is accelerating 'without any external force or torque' acting on it.how this is possible.because MASS x NET ACCELERATION OF RING =(0 FORCE) .WHICH VOILATES NEWTONS SEC. LAW

and "kaksi_guy" U said that "The centripetal force is provided by mutual concatenation of neighbouring particles"plz explain this.
and I admit that both energy and angular momentum is conserved in this case. then how newtons second law is violated.
U probably saying of tension kind of force generated in ring.but on any particle 'mutual force' acts in both direction simoultaneously.so its torque should be zero for whole ring.plz explain.
and "eyeonthes"...,"tigglys" and "Patrick C" U said that by newtons laws it is posible.plz explain it as I always knew that newtons laws say about the linear motion!!!
and plz this is not my homework and only because question is confusing I needed to asked it.

Mr. steve,ur answer seems to be the one I am looking for.but what exactly is 'd' in ur equation "T = F*d".distance between the Centre of mass and the centre of gravity or distance between the Centre of gravity and reference point on earth.plz clarify,i'll be greatful.

and kaski guy u hav a point.but i always try to keep it as simple as possible.that's why I put phrase "freely falling body" in main body of question and then I used 'particle' in ad. details to explain what my question exactly is.but i'll keep ur advice in mind in future questions.

and "pearlsawmme" U said that "The center of gravity and center of mass coincide for all objects.Hence there is no resultant torque acting on the freely falling body" U did not give any reason that why this is so I mean that why (or how) coincidence of the C.M. and C.G. of a body makes net torque zero on it.

and 'stronger_..' thanx fr that excellant link but I asked how we qualitatively explain the effect,be it however small.

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HEY PLEASE IGNORE THE SECOND ADDITIONAL DETAILS PUT ABOVE.THEY WERE FOR MY OTHER QUESTION BUT MISTAKENLY PUT HERE.I CANNOT DELETE THEM EITHER.SO I BEG UR PARDON FOR IT.

Answer 1

There are 2 conservation laws is your question: one that of energy another one of angular momentum. It does not matter what our “common sense” suggests us, these laws are implorable. That means we cannot coax them to stop working to prove our common sense.
The centripetal force is provided by mutual concatenation of neighbouring particles.

Answer 2

First, what you describe is impossible...there are always frictional forces (e.g., drag, kinetic, static, viscosity) acting on inertial mass of any kind. So, there will also be something there to slow down a moving mass no matter what its shape.

Second, Newt's laws say once a mass gets moving, it stays moving in the same manner (rotation, linear, whatever) until a net force on it changes that motion (including bringing it to a halt). So, accepting the impossible (frictionless motion), your ring will rotate forever once it is started.

Third, centripetal force in the ring is exactly offset by centrifugal force due to the change in tangential velocity (and therefore acceleration) at each "particle" or point in the ring. Thus, there is no net force here to change the ring's rotational velocity. No, I don't think there is anything (other than reality) to stop that ring.

Answer 3

This is a hypothetical question. There is no way to stop or block all forces. If this could be done, the ring once set in motion would rotate indefinitely. Being call perpetual motion.

Answer 4

Without any external forces, the ring will continue its rotary motion into eternity according to Newton's First Law of Motion.

Answer 5

Commander Gerald Carr responded that question and proved the relevent idea even as he took into area a sort gyroscope,he set it spinning and it remained spinning for the lengh of his adventure into area about seven days,really preventing on his and the crafts re get entry to into our gravity,essentialy a gyroscope is a sort of the earth with really 2 factors in contact and the speed of the airplane mandatory to exert stress and conquer the gravitational stress exerted upon that airplane is round 2300 revolutions in step with minute, once you get rid of the gravity and friction of contact then there is not something to end the rotation of that airplane, for info see viz information images skylab 1972. regards LF

Answer 6

this can be solved by newtons,F=MA[force,mass,acceleration]
we can rework this problem into M/F=A[remember that acceleration is gaining speed and losing speed].the mass is X,
the force is 0,so X/0=0.this says that the ring will nether accelerate nor decelerate.

but.....,newton laws clearly state that when their is no force on an object,it will fall into "uniform strait line motion" not uniform circular motion.

sorry,all this did was prove your question is confusing.
if it were me i would put my money on rotating forever

Answer 7

Also, if the ring is anything but perfectly electrically neutral, the motion of its excess charge will cause it to radiate, slowing it down even in the absence of other effects.

Answer 8

Bodies in motion will tend to stay in motion.

If there are no other forces - no gravity, no air, no friction - it will continue to spin forever, or until another force acts on it.

Answer 9

Is the ring being influenced by gravity, reguardless how it's shaped, it would still slow down- wouldn't it?

Answer 10

newtons law google it. & stop trying to cheat on your homework