The Laws of Newton Though dating three centuries back, the Laws of Newton, especially the third one, seen by many as the most fundamental one, are still subject of discussion and not well understood by all, not even by some scientists, as I noticed. The formulation of Netwon's three laws themselves are usually well known, as follows: An object on which no external forces are working, will persist in its momentary state of motion ¹ A force (F), accelerating an object's speed, is equal to the range of the object's mass (m) and its acceleration: [ F = m.a ] ² An acting force always generates an equally large reaction force in the opposite direction (action = reaction).
These laws sound very straight forward and perfectly clear, but when applying them, great confusion in respect to Newton's third law will arise for those who do not have a thourough insight in the implementations. Just consider you pushing against a table to move it over the floor. As per Newton's third law, the table will push back with the same force and so there would be no resulting force to move that table, though it evidently does move (if you're strong enough)! Lets further assume the case that there is no friction between the table's legs and the floor, then even a baby (being fixed to the floor itself) could move that table by pushing however light against it, just that the mass of the table, as per Newton's second law, would only cause a very small acceleration, but yet resulting in a whatever low speed, as long as the baby is pushing. Nevertheless, also here Newton's third law applies, as the accelerating table pushes back with an 'inertial force', equal to F = m.a (second law), of exactly the same strength as with which the baby is pushing - again no resulting force to move that yet moving table! If we in addition consider two equally strong persons pushing against each other with equal force, they will indeed not be able to move each other, so why does the table move? Even more confusing it becomes, when one person is stronger than the other and thus moves the weaker one, but yet Newton's third law applies here also, that the two pushing forces working against each other are equal, being one and the same contact force between the two persons! How to solve this apparent contradiction? Indeed apparent, because though you can move the table, the table cannot move you. But the stronger person, pushing against the weaker one, can move the latter, in spite of the contact force between them being one and the same. The obvious conclusion must be that the implementation of Newton's third law is, that the active force does the work involved with the motion and the reactive force does not. Clearly, the table cannot do work and thus cannot move you, but you can move the table, because your body does the required work. Likewise, the stronger person can do more work than the weaker one and thus move the latter. In generalizing these situations, we can say that an accelerated motion is not so much the result of a 'force', but rather of transfering energy from the active component to the reactive one. The resulting force that "drives" the motion, is the contact force between the two objects, pointed in the direction of the motion, or acceleration and is thus the only physically existing one. There are no physically separated action and reaction forces, but in the world of our perceptions. We can clearly see this by trying to measure these alleged forces separately - we cannot. We can only measure the contact force, the only physically existing one, neither being active, nor reactive, but rather "driving" and the numerical value of which is given by Newton's second law - the third law can actually be placed between parentheses - it only applies to our perception of events. This solves the "contradiction", there is none! With this insight, we can consider what happens, when an object describes a circular path around a fixed center point, to which it is mechanically attached. The common perception is that a so called 'centrifugal force' is acting on that object, pointed outwards in the radial direction from the center of rotation. Newton's third law requires that there is an equally large reaction force working in the opposite direction, thus pointing radially inwards to the center of rotation, the so called 'centripetal force'. Of course, either can be seen as causing the other, as being active, or reactive, which in itself is a confusing thing. Even some top scientists, such as Bernhard Haisch, whom I once had a short e-mail discussion on the matter with, claim that these two forces take each other out (as it is in any and all other cases). That sounds indeed very logical, but it brings us in conflict with Newton's first law, which would require the object to move with uniform speed along a straight line, because no (resulting) forces are working on it. Indeed, if and when the object suddenly would be disconnected from the center of rotation, centrifugal and centripetal forces cease to exist in that very same moment and the object, in compliance with Newton's first law, would thus persist in the motion it had at that very moment, being directed tangentially to the previous orbit and thus continue to move at uniform speed in that direction. This is not quite clear to many, as I had to notice in a dispute once with my employer, who has a Phd in physics(!), yet claiming the object would fly out radially. For him, the centrifugal force was a physical entity. In some practical sutations, like the rotating nozzle of a water sprinkler, one indeed observes that the leaving water rays make a certain, non perpendicular angle with the radius of the the nozzle's rotation, but every sportsman throwing a discus knows, that he must let go of the discus when his arm is perpendicular to the direction in which he wants to throw it. The difference is that the water in the sprinkler already had a radial speed on leaving the nozzle (combining with the tangential one), whereas the discus has no radial speed on being relased from the hand and thus moves out tangentially. Hence, the claimed balancing out between centrifugal and centripetal forces is definitely not the same as both not existing and thus the object in orbit cannot be in balance of forces, even though Newton's third law seems to require it. However, with the above mentioned insight we can consider the centripetal force to be the active, working one, pulling the object inwards into its circular path and being the only, physically exisisting force - there is no centrifugal force, but rather the tendency of the object to move in a straight line, as per Newton's First Law. Nevertheless, this centripetal force is not doing any work, because there is no motion in its (radial) direction..isn't there? Truly not relative the center of rotation, but in the frame of reference, in which the center of rotation is a fixed, rotating point (the frame of reference in which we, as observers, are at rest), there definitely is an accelerated motion of the object, in the direction of the centripetal force, pointed towards the center of its circular path. This acceleration causes a speed in the direction towards this center, but the vector of this speed is rotating with this fixed point in the said frame of reference and thus the resulting speed in any direction becomes zero - there is no 'traveled path'. Thus the centripetal force causes an accelerated 'motion', but yet doesn't do any net resulting work. Neither does gravity, giving your body an acceleration (weight = F = m.g) and so gravity and inertia indeed are equivalent phenomenae, as stated in Einstein's General Relativity. In conclusion, the so called centrifugal force is the apparent, physically not existing reaction force, not caused by Newton's third law, as erroneously perceived by practically all scientists (except one I know of ³ ), but by the first one, being the tendency of an object to persist in its momentary state of motion. The numerical value of this inertial force is as per Newton's second law: F = m.a This is the implementation of 'centrifugal forces' which one has to keep well in mind, when using the term - better not to use it at all, in oder to avoid confusion. However, we are still faced with the above statement that accelerated motions are caused by the transfer of energy from the active to the reactive component - where is such energy transfer in the centripetally accelerated motion of an object in circular motion? Relative the center of rotation there is no such motion, but only in the frame of reference, in which this center is rotating. This is a somewhat confusing statement, because, if this center is seen as a mathematical point, how can that rotate? In a practical model, where it has a defined cross-section area, it must rotate, or it is a fixed shaft with a bearing on it, to which the connection with the circularly moving object is attached and then this bearing becomes the rotating center. So either way, the center must rotate, of whatever nature it is and there is thus no inertial(!) frame of reference, in which it could be at rest. I say 'inertial', because a rotating frame of reference is per definition not an inertial one. Hence, if inertial forces are a consequence of Newton's first law, instead of the third one, we must indeed agree with Newton's believe in an absolue frame of reference, of whatever nature, as yet unknown, it may be. In this absolute frame of reference, the object in circular motion is accelerated but the resulting speed approches zero in the limit situation, where the angular difference of the composing speed vectors approaches zero. In this absolute frame of reference, in my view a universe beyond our means of observation, there ought to be a continuous exchange of energy from-to the object in circular motion, causing it to have inertia ('centrifugal force'), THE implementation of Newton's First Law. This non-observable universe may well be the "vacuum", the Zero Point Field (ZPF) on which Haisch-Rueda-Puthoff are doing their research⁴, but I have my own ideas on that ⁵. However, that is all very speculative. What we in more concrete terms can say about newtonian laws is, that the first one is the most, i.e. the only fundamental one, the second one is a calculation procedure and the third one has no physical meaning, but states correctly that you cannot lift yourself by pulling in your own hair - something for mechanical engineers to consider, making the third law essential for them. Hence, "inventors" claiming to have found a concept for "inertial drives" (devices that can accelerate themselves without external forces working on them), have no correct understanding of newtonian laws, especially not the third one. PS: In the International System (SI) of units, Newton's second law stands central and it has only three basic units, the kilogram for mass, the meter for length and the second for time. Thus the dimension of speed v becomes meter per second m/s and acceleration a becomes meter per square second, m/s². The unit of force F is the Newton, being equal to F = m.a., with the dimesion kgm/s². "Weight" is thus a force, emerging from gravitational acceleration (g) and your body weight, with a mass of m kg, is m.g in Newton, valid everywhere in the known universe (the pound wouldn't apply on the Moon). Energy, or work (W), is the range of force (F) and travelled way (S), thus W = F.S and the dimension becomes Newtonmeter (Nm), also called the Joule, with the dimension kgm²/s². Power (E) is the work per unit of time and so E = Nm/s, which is the Watt, or Joule per second (J/s), with the dimension kgm²/s³ (an indication that time is 3-dimensional? ⁵). Pressure is force per unit of area and is called the Pascal, Pa, with the dimension N/m², which also can be used as a measure for tensile strength and loads in materials. With this simple set-up of three basic units only, all physical entities can be calculated and defined, without the need of any conversions, but in decimals (gram, liters, kilometers, etc). Using the british imperial system of units, rather much the same as used in the USA and dating back to the 12^th century, no feeling for the relationships between work, energy, weight, mass and the Laws of Newton are present and so most, especially American and British engineers, are not confident with the basics of newtonian physics, obscured by a jungle of confusing conversions. For me as a European, it is "amazing" they yet could put a man on the Moon. How many more centuries (three have passed now), until the whole world has become "modern"? DS References: The Origin of Inertia Inertia and the Laws of Newton "The Fundamentals of Mechanics and Heat", Chapter 6.4, by Hugh D. Young, McGraw-Hill Books Company, New York 1964 Inertia as reaction of the vacuum to accelerated motion Three Dimensional Time Frame Cosmology

The Laws of Newton

Though dating three centuries back, the Laws of Newton, especially the third one, seen by many as the most fundamental one, are still subject of discussion and not well understood by all, not even by some scientists, as I noticed. The formulation of Netwon's three laws themselves are usually well known, as follows:

An object on which no external forces are working, will persist in its momentary state of motion ¹

A force (F), accelerating an object's speed, is equal to the range of the object's mass (m) and its acceleration: [ F = m.a ] ²

An acting force always generates an equally large reaction force in the opposite direction (action = reaction).

These laws sound very straight forward and perfectly clear, but when applying them, great confusion in respect to Newton's third law will arise for those who do not have a thourough insight in the implementations. Just consider you pushing against a table to move it over the floor. As per Newton's third law, the table will push back with the same force and so there would be no resulting force to move that table, though it evidently does move (if you're strong enough)! Lets further assume the case that there is no friction between the table's legs and the floor, then even a baby (being fixed to the floor itself) could move that table by pushing however light against it, just that the mass of the table, as per Newton's second law, would only cause a very small acceleration, but yet resulting in a whatever low speed, as long as the baby is pushing. Nevertheless, also here Newton's third law applies, as the accelerating table pushes back with an 'inertial force', equal to F = m.a (second law), of exactly the same strength as with which the baby is pushing - again no resulting force to move that yet moving table! If we in addition consider two equally strong persons pushing against each other with equal force, they will indeed not be able to move each other, so why does the table move? Even more confusing it becomes, when one person is stronger than the other and thus moves the weaker one, but yet Newton's third law applies here also, that the two pushing forces working against each other are equal, being one and the same contact force between the two persons! How to solve this apparent contradiction?

Indeed apparent, because though you can move the table, the table cannot move you. But the stronger person, pushing against the weaker one, can move the latter, in spite of the contact force between them being one and the same. The obvious conclusion must be that the implementation of Newton's third law is, that the active force does the work involved with the motion and the reactive force does not. Clearly, the table cannot do work and thus cannot move you, but you can move the table, because your body does the required work. Likewise, the stronger person can do more work than the weaker one and thus move the latter.

In generalizing these situations, we can say that an accelerated motion is not so much the result of a 'force', but rather of transfering energy from the active component to the reactive one. The resulting force that "drives" the motion, is the contact force between the two objects, pointed in the direction of the motion, or acceleration and is thus the only physically existing one. There are no physically separated action and reaction forces, but in the world of our perceptions. We can clearly see this by trying to measure these alleged forces separately - we cannot. We can only measure the contact force, the only physically existing one, neither being active, nor reactive, but rather "driving" and the numerical value of which is given by Newton's second law - the third law can actually be placed between parentheses - it only applies to our perception of events. This solves the "contradiction", there is none!

With this insight, we can consider what happens, when an object describes a circular path around a fixed center point, to which it is mechanically attached. The common perception is that a so called 'centrifugal force' is acting on that object, pointed outwards in the radial direction from the center of rotation. Newton's third law requires that there is an equally large reaction force working in the opposite direction, thus pointing radially inwards to the center of rotation, the so called 'centripetal force'. Of course, either can be seen as causing the other, as being active, or reactive, which in itself is a confusing thing.

Even some top scientists, such as Bernhard Haisch, whom I once had a short e-mail discussion on the matter with, claim that these two forces take each other out (as it is in any and all other cases). That sounds indeed very logical, but it brings us in conflict with Newton's first law, which would require the object to move with uniform speed along a straight line, because no (resulting) forces are working on it. Indeed, if and when the object suddenly would be disconnected from the center of rotation, centrifugal and centripetal forces cease to exist in that very same moment and the object, in compliance with Newton's first law, would thus persist in the motion it had at that very moment, being directed tangentially to the previous orbit and thus continue to move at uniform speed in that direction.

This is not quite clear to many, as I had to notice in a dispute once with my employer, who has a Phd in physics(!), yet claiming the object would fly out radially. For him, the centrifugal force was a physical entity. In some practical sutations, like the rotating nozzle of a water sprinkler, one indeed observes that the leaving water rays make a certain, non perpendicular angle with the radius of the the nozzle's rotation, but every sportsman throwing a discus knows, that he must let go of the discus when his arm is perpendicular to the direction in which he wants to throw it. The difference is that the water in the sprinkler already had a radial speed on leaving the nozzle (combining with the tangential one), whereas the discus has no radial speed on being relased from the hand and thus moves out tangentially.

Hence, the claimed balancing out between centrifugal and centripetal forces is definitely not the same as both not existing and thus the object in orbit cannot be in balance of forces, even though Newton's third law seems to require it. However, with the above mentioned insight we can consider the centripetal force to be the active, working one, pulling the object inwards into its circular path and being the only, physically exisisting force - there is no centrifugal force, but rather the tendency of the object to move in a straight line, as per Newton's First Law. Nevertheless, this centripetal force is not doing any work, because there is no motion in its (radial) direction..isn't there?

Truly not relative the center of rotation, but in the frame of reference, in which the center of rotation is a fixed, rotating point (the frame of reference in which we, as observers, are at rest), there definitely is an accelerated motion of the object, in the direction of the centripetal force, pointed towards the center of its circular path. This acceleration causes a speed in the direction towards this center, but the vector of this speed is rotating with this fixed point in the said frame of reference and thus the resulting speed in any direction becomes zero - there is no 'traveled path'. Thus the centripetal force causes an accelerated 'motion', but yet doesn't do any net resulting work. Neither does gravity, giving your body an acceleration (weight = F = m.g) and so gravity and inertia indeed are equivalent phenomenae, as stated in Einstein's General Relativity.

In conclusion, the so called centrifugal force is the apparent, physically not existing reaction force, not caused by Newton's third law, as erroneously perceived by practically all scientists (except one I know of ³ ), but by the first one, being the tendency of an object to persist in its momentary state of motion. The numerical value of this inertial force is as per Newton's second law: F = m.a This is the implementation of 'centrifugal forces' which one has to keep well in mind, when using the term - better not to use it at all, in oder to avoid confusion.

However, we are still faced with the above statement that accelerated motions are caused by the transfer of energy from the active to the reactive component - where is such energy transfer in the centripetally accelerated motion of an object in circular motion? Relative the center of rotation there is no such motion, but only in the frame of reference, in which this center is rotating. This is a somewhat confusing statement, because, if this center is seen as a mathematical point, how can that rotate? In a practical model, where it has a defined cross-section area, it must rotate, or it is a fixed shaft with a bearing on it, to which the connection with the circularly moving object is attached and then this bearing becomes the rotating center. So either way, the center must rotate, of whatever nature it is and there is thus no inertial(!) frame of reference, in which it could be at rest. I say 'inertial', because a rotating frame of reference is per definition not an inertial one.

Hence, if inertial forces are a consequence of Newton's first law, instead of the third one, we must indeed agree with Newton's believe in an absolue frame of reference, of whatever nature, as yet unknown, it may be. In this absolute frame of reference, the object in circular motion is accelerated but the resulting speed approches zero in the limit situation, where the angular difference of the composing speed vectors approaches zero. In this absolute frame of reference, in my view a universe beyond our means of observation, there ought to be a continuous exchange of energy from-to the object in circular motion, causing it to have inertia ('centrifugal force'), THE implementation of Newton's First Law. This non-observable universe may well be the "vacuum", the Zero Point Field (ZPF) on which Haisch-Rueda-Puthoff are doing their research⁴, but I have my own ideas on that ⁵. However, that is all very speculative.

What we in more concrete terms can say about newtonian laws is, that the first one is the most, i.e. the only fundamental one, the second one is a calculation procedure and the third one has no physical meaning, but states correctly that you cannot lift yourself by pulling in your own hair - something for mechanical engineers to consider, making the third law essential for them. Hence, "inventors" claiming to have found a concept for "inertial drives" (devices that can accelerate themselves without external forces working on them), have no correct understanding of newtonian laws, especially not the third one.

PS: In the International System (SI) of units, Newton's second law stands central and it has only three basic units, the kilogram for mass, the meter for length and the second for time. Thus the dimension of speed v becomes meter per second m/s and acceleration a becomes meter per square second, m/s². The unit of force F is the Newton, being equal to F = m.a., with the dimesion kgm/s². "Weight" is thus a force, emerging from gravitational acceleration (g) and your body weight, with a mass of m kg, is m.g in Newton, valid everywhere in the known universe (the pound wouldn't apply on the Moon). Energy, or work (W), is the range of force (F) and travelled way (S), thus W = F.S and the dimension becomes Newtonmeter (Nm), also called the Joule, with the dimension kgm²/s². Power (E) is the work per unit of time and so E = Nm/s, which is the Watt, or Joule per second (J/s), with the dimension kgm²/s³ (an indication that time is 3-dimensional? ⁵). Pressure is force per unit of area and is called the Pascal, Pa, with the dimension N/m², which also can be used as a measure for tensile strength and loads in materials. With this simple set-up of three basic units only, all physical entities can be calculated and defined, without the need of any conversions, but in decimals (gram, liters, kilometers, etc).

Using the british imperial system of units, rather much the same as used in the USA and dating back to the 12^th century, no feeling for the relationships between work, energy, weight, mass and the Laws of Newton are present and so most, especially American and British engineers, are not confident with the basics of newtonian physics, obscured by a jungle of confusing conversions. For me as a European, it is "amazing" they yet could put a man on the Moon. How many more centuries (three have passed now), until the whole world has become "modern"? DS

References:

The Origin of Inertia
Inertia and the Laws of Newton
"The Fundamentals of Mechanics and Heat", Chapter 6.4,
by Hugh D. Young, McGraw-Hill Books Company, New York 1964
Inertia as reaction of the vacuum to accelerated motion
Three Dimensional Time Frame Cosmology