Science tries to learn the reasons.
Purposes are fairy tales we tell ourselves because we are afraid of the dark. The universe is indifferent to us. The sooner we understand that, the better.

If you want to make the universe meaningful, go out and do something about it. You have the power. But don’t expect it to hold your hand.

“The most terrifying fact about the universe is not that it is hostile but that it is indifferent, but if we can come to terms with the indifference, then our existence as a species can have genuine meaning. However vast the darkness, we must supply our own light.” — Stanley Kubrick

A moving object has kinetic energy that depends on how much velocity it has. It changes speed by accelerating (acceleration means “change of velocity”, nothing else). In fact, sometimes it is abbreviated as delta-V, Capital Greek Delta is shorthand for ‘change’. It doesn’t matter how it accelerated, how long it took or where or when it happened, or how many times you accelerated to that speed, it just matters how fast it is going. In other words, the acceleration is not important, it is just the velocity that is important.

Your sentence about the field around a hammer makes no physical sense. I suspect you visualize a hammer as being surrounded by a cloud of something. It isn’t. In physics, just because a sentence is grammatically correct doesn’t mean it has anything to do with the real world.

Your making all this more complicated than it really is, and you are inventing things that you feel are required in order to explain that complexity.

A mass stationary to its surroundings has no kinetic energy.

If the mass moves, it is experiencing a force, whether it be from the curvature of space time (gravity) or a hammer.

The change in velocity of that mass is its acceleration, its mass times the acceleration is the force on it.
(F = ma). In the case of the hammer, the force and acceleration occur very quickly.
If the mass is falling, the acceleration and force are constant and gradual.

When the acceleration stops the mass continues at a constant velocity, v = at = change in position with respect to time.

Once the mass is traveling at that velocity it has kinetic energy E = 1/2mv**2.

All of these numbers and letters have to do with the mass and its motion, they do not come from any field. The motion comes from a force, which implies contact with another mass or a gravitational force.

Consider a stationary ball on a billiard table. It is approached by another identical ball moving at some velocity v. When the second ball hits the first, its kinetic energy is now available to both balls to share. One or both of them will now be moving so that their combined kinetic energy is the same as the original kinetic energy that existed before the collision.

You don’t know enough physics yet to predict what will happen, (because you haven’t learned about momentum, another little bookkeeping tool physicists use) so I’ll tell you.

The first ball accelerates to a full stop. The second ball accelerates into motion.
That is, the second ball exerts a force on the first, causing that mass to accelerate. The second ball exerts an equal and opposite force to the first, causing it to stop. F = ma. And forces always occur in equal and opposite pairs according to Newton.

The second ball is now moving at the same speed as the first one was, so it has the same energy. In fact, the total energy available before and after the collision is conserved (we ignore friction with the air, the cloth surface of the table, etc)

Now how do we know that the second ball stops cold and the first ball takes off with its speed? Because I spent too much of my youth playing billiards, and because of the law of conservation of momentum. Experience (that is, observation and experiment)has taught us than in all interactions, energy and momentum are conserved, they do not change before and after there is an exchange of forces. In order for energy and momentum to be conserved we have defined these quantities so that they are. Conservation of momentum is what tells you how the energy involved in that collision wull be shared between the two balls. Conservation of energy tells you how much is available to be shared.

The last time I explained this to you (you obviously were not listening) I used the example of an astronaut firing a pistol in weightless space, and by knowing the mass and velocity of both the astronaut and the bullet, it was possible to calculate how fast the astronaut would recoil. Since both energy (1/2mv**2) and momentum (mv) are conserved, you know that the potential energy available in the cartridge gunpowder will be divided between the man and the bullet (but not equally, since they have different masses. The momentum is also conserved, and it is zero, at the beginning of the experiment, so it must be zero afterwards.

The momentum of the bullet is mv.
The momentum of the man is MV (we’ll use uppercase for the man). They add up to zero, so mv = MV.
Rearranging, m/M = V/v. The ratio of velocities is the inverse of the mass ratio, so if the man, spacesuit and pistol weigh, say, 500 times as much as the bullet, they will recoil at a velocity 1/500 as fast. (I ignore what happens to the gases of the gunpowder combustion, etc.)

The point I’m making is that with the laws of conservation of energy and momentum you can always determine how masses and velocities are shared (through exchange of forces) in collisions, rockets, orbits, explosions, pendulums, rotating bodies, springs, bouncing balls, electrons in magnetic fields–whatever.

You don’t need to know “where it comes from”. All science cares is what happens, not why. That way lies madness.

The energy you put into the ball was the result of “work”. The energy of the work you perfored came from Chemical Potential Energy in your body, unlocked by burning calories.

According to the law of Conservation of Energy, there is a constant amount of energy in an “isolated” system. The energy of the calories is turned into work, and is stored in the ball when it is lifted. When the ball (lets say it’s a bowling ball for dramatic effect) is released, gravitational potential energy takes the form of kinetic energy. When the ball hit’s the ground the energy is converted back to heat and sound (the kinetic energy of air molecules). The heat is dissipated but remains in the system and so does the energy of sound the waves.

It’s interesting to note by lifting the ball you increased it’s potential energy relative to the surface but you decreased the force of gravity between the center of the earth and the center of the ball.

As I understand English language: If I “acquire” money, I will be richer than I was before acquiring it, but if I “have” money, then I may or may not be rich. If mass moves, it “has” energy, if it “accelerates” then it “acquires” kinetic energy. Am I missing something here.
Hmmm…Time does come into the equation, if I only acquire little bit of money over a long period of time it will take a very long time for me to become very rich.

Confusion again: You say: “The acceleration has nothing to do with the kinetic energy”
Then you say: “velocity = acceleration x time.” Is velocity not associated with the quantity of kinetic energy?

You say that: “As for your idea of a “force field”, there is no such thing.”
I can understand that a moving hammer can force a nail into wood, and that is true as long as there is a large enough “field“ around the head of the nail to give room for the hammer movement. Question; is it not a “force” that moves the hammer in the first place?

I agree that; the acceleration of a falling object is different on a different celestial body, and I agree that the massive object will have greater force that the light object when they hit the ground. And I agree that they will hit the ground at the same time if dropped from the same height, provided that there is no resistance from the atmosphere. The question still is: If there is no “field” then what causes the acceleration?

You said: “Energy, matter, space and time. That’s all you need, no spooky forces or magic energy reservoirs, or Jeddi force fields.”
Was it Hans Solo that said something to that effect in Star Wars?
I agree that space, mass and energy is all we need, but I would add “in this life”;-) I omit time, because time is included in the energy part. As in: E=mc^2

You said: “And one more thing, there is no such thing as a “field”.
I do not agree, because I do not understand how a “mathematical concept” alone could cause the acceleration of mass.

You said: “The field does not “give” energy to objects moving through it, or it would eventually have to run out of energy, right?”
I’m not quite sure about that, earlier we touched on the subject of potential and kinetic energy exchange. If; as you said previously, there is a balance of kinetic and potential (for) energy in the universe, then when the kinetic increases the potential must decrease to keep everything in balance, but at some point the kinetic energy could decrease and the potential would increase. That implies a sinusoidal oscillation. Perhaps the whole universe is just an oscillation of energy states.

a) “when a mass moves it acquires kinetic energy”
Yes you can calculate it exactly, the kinetic energy is 1/2 mv**2.
However the velocity v is always relative to some arbitrary coordinate system, it is a geometric concept, not a physical one. The kinetic energy of a falling rock is only apparent when it strikes the ground. To an insect standing on the rock, unaware of the ground, there is no way to determine that kinetic energy until after the collision.

b)The acceleration has nothing to do with the kinetic energy. The kinetic energy is determined by the speed of the moving mass, by 1/2mv**2. It doesn’t matter if the acceleration leading to that velocity was high or low, quick or spread out over time. A 1 kilogram mass moving at 10 meters per second has an kinetic energy of 50 Joules. It doesn’t matter if that mass fell on earth where the acceleration is 9.8 meters per second squared, or on the moon where it is 1/6 as much. The velocity matters, not the acceleration. But remember, velocity = acceleration x time. On the moon it would have to fall for six times as long a time to reach the same speed as on earth.

As for your idea of a “force field”, there is no such thing. A force is what happens when a mass is accelerated, either by gravity, or a rocket motor, or because someone shoves on it. No field is needed. A force is something the mass does, not something that happens to the mass. A force is a mass times an acceleration, so the force acting on a 1 kg stone falling in the earth’s gravity is F = ma = 9.8 Newtons. A 1000 kg automobile falling alongside it experiences a force of 9800 Newtons. If these objects were falling on the moon the forces on both would be one sixth as much. You will note the force is different for the stone and the car because the masses are different, not because “the field” is different. They are falling together, at the exact same speed, accelerating in exactly the same way. Only the mass is different.

By the way, a “Newton” is defined as 1 kg meter per second per second, or kg-m/s**2. A force acting on a mass over a distance is what gives that mass its energy. So a force of one Newton acting on a mass of 1 kg over a distance of 1 meter gives you an energy of one Joule.

Our one kilogram stone falling off a 100 meter building will have experienced a force of 9.8 Newtons across a distance of 100 meters, so it will have a kinetic energy when it hits of 980 Joules. We know the energy of a moving object is 1/2mv**2, so solving our 1 kg mass for v we get v = SQRT (2x 980) = 44.3 m/s. We know that the definition of velocity is acceleration times time, so 44.3 = 9.8t, so t = 4.5 s. Calculus can be used on these equations to reveal that the distance traveled d = 1/2 at**2. So going to our example of a 1 Kg brick falling off a 100 m building, the time it takes to reach the ground is 4.5 seconds, the speed when it hits is 44.3 m/s, the energy it releases on impact is 980 Joules. The equations can all be used to check each other, and we can physically measure the mass with a scale, the distances with a ruler, the time with a clock. The energy ties it all together.
Energy, matter, space and time. That’s all you need, no spooky forces or magic energy reservoirs, or Jeddi force fields..

And one more thing, there is no such thing as a “field”. The field is a mathematical concept obeying certain rules that allows us to calculate what those forces will be. Mathematically speaking, it is a ‘three dimensional vector space’ not an object or thing. They are useful in calculating gravity and electromagnetic problems, just like latitude and longitude are useful for navigation. But it has no real existence itself. When a physicist says something like a gravitational or magnetic field he is really referring to a mathematical equation that yields a force vector ponting towards or away from the center and with a magnitude equal to a constant times 1/distance from the center squared when a test charge or mass is placed at any point within it. It is a mathematical model, not a thing like a magic cloud with special properties. It’s all in your mind.

Four centuries ago Newton thought of it as a thing that somehow powered other things to move, he called it “action at a distance” and he was (correctly, as it turns out) very suspicious of that explanation. Einstein later showed us it was a geometrical phenomenon, caused by the curvature of space-time. The field does not “give” energy to objects moving through it, or it would eventually have to run out of energy, right?

To summarize, in Newtonian mechanics, the fundamental quantities are matter (m), energy (E), space (d), and time (t). The units of each are kilograms, Joules, meters, and seconds.

velocity: v =d/t
acceleration: a = v/t
distance d = 1/2at**2
force: F = ma
Energy E = Fd = 1/2mv**2

and one we haven’t discussed, but which can come in very handy, momentum p = mv

a) “ A mass when moving has kinetic energy.
b) “If you carry a mass to the top of a building, it is said “to have potential energy mgh relative to the ground.”
c) “if that stone drops from the building it will hit the ground at a certain speed, hence a certain kinetic energy 1/2mv**2. That is real energy, capable of doing work,
d) “Potential energy is not a thing”

The following points that you make are unclear to me, “if” I try to understand them from your perspective.

a) “When a mass moves, it acquires kinetic energy.“

I would qualify this by saying that; when a mass moves it “contains” kinetic energy and when it “accelerates” it acquires kinetic energy.

b) “The potential energy is only a number that tells you how much kinetic energy you’ll get after the stone drops. It has no reality in itself.”

I agree that the numbers will tell you the amount of kinetic energy at any point in the acceleration path, but the numbers are not the cause of the acceleration, the cause (like you said ) is a “force” and that force exists in a “field“, such as a gravitational field. Since the field contains the force, and causes the acceleration, the field must contain the “potential” for the kinetic form of energy. This explanation does not negate the use of numbers to express quantity, It simply states that; a force within a field is needed to accelerate mass. In other words the forcefield contains the “potential” for (kinetic) energy. In the case of a falling object, the forcefield is gravity and in the rocket propulsion it is usually caused by the forcefield within the chemical structures, although in some cases by electronic and/or magnetic fields.

So: “Que la fuerza esté con vosotros”, como dicen en Star Wars.

This type of a friendly dialog about differing opinions is what I enjoy about the HZ.

If you carry a mass to the top of a building, it is said “to have potential energy mgh relative to the ground.” This does not mean it contains this energy locked up inside it, waiting to escape like a genii in a bottle.

What the phrase in quotes above means is that if that stone drops from the building it will hit the ground at a certain speed, hence a certain kinetic energy 1/2mv**2. That is real energy, capable of doing work, like putting a dent in the pavement.

The potential energy is only a number that tells you how much kinetic energy you’ll get after the stone drops. It has no reality in itself.

You will note potential energy is measured relative to the ground, it is how much energy the stone will add by falling to the ground.

Let’s assume you now dig a very deep hole on the spot where the stone will hit. Let’s say that hole is as deep as the building is tall. So when the stone hits the bottom of the hole it will be moving much faster, in fact it will have twice the kinetic energy because the stone fell twice as far. You have added extra potential energy to the stone without even touching it, or doing anything to the stone; you just dug a hole in front of it (in other words, you changed the value of h). You have just redefined what the potential is relative to.

The potential energy is not a property of the stone, it is a property of how far the stone is from the spot where it strikes. That stone has a potential energy relative to the bottom of the hole, it has half that potential energy relative to the street, it has a different potential energy relative to every floor of the building. And it will have zero potential energy relative to the spot on the roof where it rests at the start of the experiment. Potential energy is not a thing, its a place.

When a mass moves, it acquires kinetic energy. Where does it come from? Because a force acted on it, causing it to move. What is a force? Its what happens when a mass is accelerated. What is an acceleration? Its a change in velocity. What is velocity? A change in location.

Energy is just mathematical combinations of matter, space and time. Its just a word for how a moving object is different from a stationary one. It is not a thing, it is a relationship between things.

I’m sorry, that’s all there is to it. And I can’t explain it any better than that.

Yes: Finnish is correct, and
I’d like to know how to discern accent from written words?