author=bistander link=topic=4661.msg112274#msg112274 date=1716211632
What is gravity, or gravitational field made up of? I don't know. But that lack of the true nature doesn't prevent detailed characterization of the phenomenon and intelligent applications. No doubt we could do better if we knew the answer to your question. And I'm sure many smart people strive to find the answer for us.
So, this would be the same as- i know i can drive a car down the road, but have no idea as to how the car is actually propelled down the road.
Thankfully, some people took the time to learn exactly how that car is propelled down the road, which led to vast improvements in that propelling system, right down to the liquid energy it self.
(Do you believe that every force has an equal and opposite force ?)
Yes.
I accept as true Newton's Law, Gauss's Law, Ohm's Law, Ampere's Law, and pretty much the body of scientific knowledge as taught to me long ago. Using these principles over a long career in the field, applying them daily, I've witnessed no exceptions. For my humble self, I pushed some limits. I choose to rely on these and reject the theories put forth by the likes of Ken Wheeler, Albert Roy and Walter Rawls, Wesley W. Gary, and a few others referred to on this thread thread.
That is simply not the case.
If every force had an equal and opposite force, we could never accelerate a mass, which we know we can.
Most fail to stand back, and look at the big picture, and look only at a single point in applied forces.
If the total reacting forces of a mass are equal to, and opposite of the acting forces(applied forces), then that mass would not accelerate.
In order for a mass to accelerate, the total applied forces must be greater than the total reacting forces of that mass.
Only the total energy applied is equal to the total energy stored and dissipated.
I will give you a simple example below.
Here we have a man pushing on a car, where as the applied force is just under that required to get the car moving.
In the top pic, the car is not moving, and the reacting forces A and C, are equal to and opposite of the acting forces B and D
In the second pic, the man increases force D, which results in the same increase of forces A and B
So now forces A, B, and D are equal, but force C remains close to the same-the rolling resistance force of the wheels on the road.
The car is now being accelerated forward, due to the total of forces B and D being greater than the total of the reacting forces of A and C.
But energy is still being conserved, where some of the energy being applied is used to overcome that which reaction force C applied (dissipated energy), and some of that applied energy is being stored as kinetic energy in the accelerating mass (the car).
So, all energy applied to the car is equal to all energy dissipated by the car through friction and heat, and energy stored as kinetic energy.
But the sum total of acting forces (applied forces), must be greater than that of the reacting forces, in order for that car to be accelerated.
The stored kinetic energy has to come from somewhere, and energy will only flow from a high state to a lower state (the second law of thermodynamics), which also tells us that the cars total sum of reacting forces is lower than the acting forces placed upon it once the car began to accelerate.
I think, like most, you look at only forces A and B, in which you would be correct--the reacting force is equal to and opposite of that of the acting force.
But when you take into account the total forces, which include forces C and D, then the sum total of forces is never equal and opposite when a mass is being accelerated.
Work done against friction: W = Ff x. Energy is the quantity that can be used to perform work.
So if the car is pushing back just as hard as the man is pushing the car, then the car is doing just as much work on the man, as the man is doing on the car, over the same distance.
This means the sum total of energy applied to the car by the man, is the exact same amount of energy that is applied to the man, by the car.
You then need to explain as to where the stored kinetic energy came from, that is now stored in the moving car.
The kinetic energy that is building up in the car as it accelerates, comes from the imbalance of applied forces over distance-the imbalance of work done between the man and the car.
So, would not you agree, in order for a mass to be accelerated, such as the car, the acting force (the applied force) must be greater than the reacting force
Brad
Never let your schooling get in the way of your education.