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The Usborne Illustrated Dictionary of Physics: The Facts You Need to Know-At a Glance
-- Indispensable homework aids and reference sources
-- Definitions supported by detailed pictures and diagrams
-- Topics arranged thematically so that words are explained in context
-- Fully integrated system of cross referencing plus a comprehensive index
-- Definitions supported by detailed pictures and diagrams
-- Topics arranged thematically so that words are explained in context
-- Fully integrated system of cross referencing plus a comprehensive index
128 pages, Paperback
First published September 1, 1988
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Displaying 1 - 3 of 3 reviews
December 16, 2023
The book defines force as that which influences the shape and movement of an object. It lists gravitational, magnetic, electric, and nuclear as the main forces. Dynamics is the relationship between an object and the forces acting on it, which I take to mean that forces are the effects on an object. The region in which a force has an effect is called a “force field,” which seems to operate in critical distance units, per the inverse square law.
At the end of the book is a handy chart that compares gravitational, electromagnetic (electro force is static, and magnetic is electric force that is moving or something like that, i.e. “The force is between two objects in which current is flowing”). Whereas gravity is said to be an attractive force only, electro-magnetic involves both attraction and repulsion. For the electric force, opposites attract; same charges repel. For a magnetic force, current that flows in the same direction is attractive; current that flows in the opposite direction is repulsive.
This is the standard understanding of forces. The problem is understanding gravity as an attractive force only, which seems to be a legacy of Newton’s classical physics: Two bodies mysteriously influence each other via an “attractive force.” Einstein said there was no force like that at all between two bodies. Rather, force dynamics were geometric in nature and the movement of a smaller mass is toward a larger mass that has concentrated the fabric of space around itself, which thereby directs the movement toward its gravitational center. There’s a force involved, but it’s not in this sense of some internal property inside each mass that grabs the other. Rather, it’s merely following a line of movement toward a gravitational center.
So, yes, there’s a force (movement is directed by the curvature of space), but it’s not really about an “attraction” force at all, like the electro- and magnetic forces. That’s one problem with understanding gravity as an attractive force. The other is that the flip notion, “resistance,” is not part of the discussion about gravity, as it is with the electro-magnetic forces. Per Einstein, following the lines of geometric curvature (toward the gravitational center), what keeps the lesser mass from merging with the larger mass? Why, in other words, are their orbits? Well, here too isn't this another problem with Newton’s formulation in the sense that he focuses on the acceleration side, but not on the inertial movement question per his 2nd law: A body “wants” to stay at rest or continue its straight-line motion, and this “wanting” factor is what counterbalances (speed and distance are also involved) that pull inward, which creates orbiting. Inertial movement, in other words, is a resisting-repulsive factor and the dynamic tension toward and against continues until a state of balance is reached.*
The book describes energy, again in a standard way, as the capacity to do work, i.e. to move an object. Isn’t this definition a legacy of the budding industrial age that relied upon energy, but doesn’t it minimize the central role of “energy” in the cosmos? For example, Einstein’s formulation that matter is energy and energy is matter, and that both are mass (relative degrees of concentrated energy, with pure energy being massless in a rest state (matter) but retaining its mass as kinetic energy. And, given gravity’s central role in cosmological structures, including possibly, the structure of the cosmos as a whole, it is integrally bound up with mass, which is to say concentrated “energy” that somehow creates geometric curvature fields of gravitational force and all movement within such fields.
Of course, gravity’s flip side is light, which is liberated matter bound in mass. So, what creates movement now? There’s gravity’s geometric space that accelerates bodily movement on the one hand, and there’s light and its heat, emanating from within a body, that moves outward on the other. Energy moves inward and moves outward, so what is it exactly? I’ve seen nothing good that describes its absolute central factor within the cosmos. Whatever it is, it’s certainly more than “the capacity to do work.”
*Seen this way, physical force is seen as the dynamic expressed between toward and against, with states of equilibrium being the resolution (with zero differentials between the two bodies), and this suggest that a Hegel-like dynamic (pushing toward, pushing against, and resolution of energetic differentials) is built into the structure of the universe.
At the end of the book is a handy chart that compares gravitational, electromagnetic (electro force is static, and magnetic is electric force that is moving or something like that, i.e. “The force is between two objects in which current is flowing”). Whereas gravity is said to be an attractive force only, electro-magnetic involves both attraction and repulsion. For the electric force, opposites attract; same charges repel. For a magnetic force, current that flows in the same direction is attractive; current that flows in the opposite direction is repulsive.
This is the standard understanding of forces. The problem is understanding gravity as an attractive force only, which seems to be a legacy of Newton’s classical physics: Two bodies mysteriously influence each other via an “attractive force.” Einstein said there was no force like that at all between two bodies. Rather, force dynamics were geometric in nature and the movement of a smaller mass is toward a larger mass that has concentrated the fabric of space around itself, which thereby directs the movement toward its gravitational center. There’s a force involved, but it’s not in this sense of some internal property inside each mass that grabs the other. Rather, it’s merely following a line of movement toward a gravitational center.
So, yes, there’s a force (movement is directed by the curvature of space), but it’s not really about an “attraction” force at all, like the electro- and magnetic forces. That’s one problem with understanding gravity as an attractive force. The other is that the flip notion, “resistance,” is not part of the discussion about gravity, as it is with the electro-magnetic forces. Per Einstein, following the lines of geometric curvature (toward the gravitational center), what keeps the lesser mass from merging with the larger mass? Why, in other words, are their orbits? Well, here too isn't this another problem with Newton’s formulation in the sense that he focuses on the acceleration side, but not on the inertial movement question per his 2nd law: A body “wants” to stay at rest or continue its straight-line motion, and this “wanting” factor is what counterbalances (speed and distance are also involved) that pull inward, which creates orbiting. Inertial movement, in other words, is a resisting-repulsive factor and the dynamic tension toward and against continues until a state of balance is reached.*
The book describes energy, again in a standard way, as the capacity to do work, i.e. to move an object. Isn’t this definition a legacy of the budding industrial age that relied upon energy, but doesn’t it minimize the central role of “energy” in the cosmos? For example, Einstein’s formulation that matter is energy and energy is matter, and that both are mass (relative degrees of concentrated energy, with pure energy being massless in a rest state (matter) but retaining its mass as kinetic energy. And, given gravity’s central role in cosmological structures, including possibly, the structure of the cosmos as a whole, it is integrally bound up with mass, which is to say concentrated “energy” that somehow creates geometric curvature fields of gravitational force and all movement within such fields.
Of course, gravity’s flip side is light, which is liberated matter bound in mass. So, what creates movement now? There’s gravity’s geometric space that accelerates bodily movement on the one hand, and there’s light and its heat, emanating from within a body, that moves outward on the other. Energy moves inward and moves outward, so what is it exactly? I’ve seen nothing good that describes its absolute central factor within the cosmos. Whatever it is, it’s certainly more than “the capacity to do work.”
*Seen this way, physical force is seen as the dynamic expressed between toward and against, with states of equilibrium being the resolution (with zero differentials between the two bodies), and this suggest that a Hegel-like dynamic (pushing toward, pushing against, and resolution of energetic differentials) is built into the structure of the universe.
November 18, 2020
It is an interesting book packed with information about physics.
Displaying 1 - 3 of 3 reviews