Reaction-Action-Activities relationship?
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From: Saimhain Moose on 18 Mar 2010 11:46 On Mar 18, 6:28 am, Kumar <lordshiva5...(a)gmail.com> wrote: > On Mar 18, 9:49 am, Saimhain Moose <samhainmo...(a)hotmail.com> wrote: > > > On Mar 18, 12:21 am, Kumar <lordshiva5...(a)gmail.com> wrote: > > > > Are activities not dependant on applied forces? > > > Exactly what do you mean by "activities"? > > Something done as an action or a movement. What do you mean by "thing", "action", and "movement"? Years ago, Abian tried to justify chemical and physical behavior by applying human psychology to inanimate objects and substances. I get the feeling that you are making the equal-and-opposite error of trying to explain human behavior with simple laws of physics that describe mechanical properties of objects.
From: jbriggs444 on 18 Mar 2010 16:05 On Mar 16, 7:35 am, Kumar <lordshiva5...(a)gmail.com> wrote: > Hello, > > Newton's third law is frequently stated > > "Action and reaction are equal and opposite > To every action there is an equal and opposite reaction" > > Law is defined as; > > The term law is often used to refer to universal principles that > describe the fundamental nature of something, to universal properties > and relationships between things, or to descriptions that purport to > explain these principles and relationships.http://en.wikipedia.org/wiki/Law_(principle) > > I have some questions:- > > 1. Is it also true that "to every reaction there is equal and opposite > action"? In context, yes. Unfortunately, the terms "action" and "reaction" as Newton used them have some rather specific meanings that are nothing at all like someone might guess based on their common English meanings. Newton was writing centuries ago He was inventing new concepts and casting them in Latin. We can forgive him if translations use words with meanings that are not what you might expect. " Lex III: Actioni contrariam semper et æqualem esse reactionem: sive corporum duorum actiones in se mutuo semper esse æquales et in partes contrarias dirigi. " Translation: ''To every action there is always an equal and opposite reaction: or the forces of two bodies on each other are always equal and are directed in opposite directions''. The modern phraseology is best captured by this last bit: "The forces of two bodies on each other are always equal and are directed in opposite directions". > 2. Can we consider action or reaction as activities or motions and as > law hold universal application, whether above action reaction > relationship will apply to all our activities? No. Don't be silly. You don't take a statement using words whose meanings are already a bit "off", squeeze it into another context entirely and make the excuse that the word "Law" gives you good reason to expect that the result is both sensible and truthful. The third law is a reasonably universal law of physics. That does not mean that it passes muster as a law of human psychology, biology, English jurisprudence, chess or action movies. You can't learn physics by language lawyering the Principia badly.
From: Kumar on 19 Mar 2010 00:27 On Mar 18, 6:35 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Mar 18, 5:30 am, Kumar <lordshiva5...(a)gmail.com> wrote: > > > > > > > On Mar 17, 7:33 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Mar 16, 6:35 am, Kumar <lordshiva5...(a)gmail.com> wrote: > > > > > Hello, > > > > > Newton's third law is frequently stated > > > > > "Action and reaction are equal and opposite > > > > To every action there is an equal and opposite reaction" > > > > > Law is defined as; > > > > > The term law is often used to refer to universal principles that > > > > describe the fundamental nature of something, to universal properties > > > > and relationships between things, or to descriptions that purport to > > > > explain these principles and relationships.http://en.wikipedia.org/wiki/Law_(principle) > > > > > I have some questions:- > > > > > 1. Is it also true that "to every reaction there is equal and opposite > > > > action"? > > > > > 2. Can we consider action or reaction as activities or motions and as > > > > law hold universal application, whether above action reaction > > > > relationship will apply to all our activities? > > > > > Best wishes. > > > > The better way to say the third law is thus: > > > Interactions between bodies are always pairwise, so that what A exerts > > > on B, B exerts on A, in equal amount but in the opposite direction. > > > > "Exert" here is taken to mean either a force or a momentum transfer. > > > It does NOT mean the response to that exertion, which is seen as > > > motion of the body. > > > > As an example of this last distinction, consider the collision of a > > > mosquito with the windshield of a speeding truck. The force the > > > mosquito exerts on the truck is just as big as the force the truck > > > exerts on the mosquito. The momentum transferred from the mosquito to > > > the truck is just as big as the momentum transferred from the truck to > > > the mosquito. But the change in motion of the mosquito (the response > > > to the truck's interaction with it) is much larger than the change of > > > motion of the truck. > > > > PD- Hide quoted text - > > > > - Show quoted text - > > > When a rubber ball hit to a wall it came back to us but not an iron > > ball? How it is justified in newtons 3rd law? > > The transfer of momentum to the rubber ball is twice what it is to the > iron ball. But the momentum transferred to the rubber ball is equal > and opposite the momentum transferred to the wall in that collision. > And the momentum transferred to the iron ball is equal and opposite > the momentum transferred to the wall in that collision.- Hide quoted text - > > - Show quoted text - If iron ball is thrown towards wall with equal momentum to rubber ball, will iron ball return similar to rubber ball?
From: Kumar on 19 Mar 2010 00:29 On Mar 18, 6:36 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Mar 18, 5:28 am, Kumar <lordshiva5...(a)gmail.com> wrote: > > > On Mar 18, 9:49 am, Saimhain Moose <samhainmo...(a)hotmail.com> wrote: > > > > On Mar 18, 12:21 am, Kumar <lordshiva5...(a)gmail.com> wrote: > > > > > Are activities not dependant on applied forces? > > > > Exactly what do you mean by "activities"? > > > Something done as an action or a movement. > > They're not the same. A movement (specifically a change in movement) > is the *response* to a force. The force is the cause, the acceleration > is the effect. Motion is not a cause. What is the differance between acceleration & motion?
From: Kumar on 19 Mar 2010 00:31
On Mar 18, 8:46 pm, Saimhain Moose <samhainmo...(a)hotmail.com> wrote: > On Mar 18, 6:28 am, Kumar <lordshiva5...(a)gmail.com> wrote: > > > On Mar 18, 9:49 am, Saimhain Moose <samhainmo...(a)hotmail.com> wrote: > > > > On Mar 18, 12:21 am, Kumar <lordshiva5...(a)gmail.com> wrote: > > > > > Are activities not dependant on applied forces? > > > > Exactly what do you mean by "activities"? > > > Something done as an action or a movement. > > What do you mean by "thing", "action", and "movement"? > > Years ago, Abian tried to justify chemical and physical > behavior by applying human psychology to inanimate > objects and substances. I get the feeling that you are > making the equal-and-opposite error of trying to explain > human behavior with simple laws of physics that describe > mechanical properties of objects. Whether somewhat equal & opposite reaction (discounted by resistances in any) is not seen in many other activities? |