speed weight

[frii143]

you only have to pump up water one foot at any hight. if it is dropped at hight it would give you speed weight that more then its took pump it up. if you had a tower with two pockets a full one and an empty one the impacted could be hit a lever at the bottom that spins a generator to pump water to the top of the tower.

[Paul-R]

you only have to pump up water one foot at any hight. if it is dropped at hight it would give you speed weight that more then its took pump it up...

I think you'll find that the energies involved are the same, less the losses.

[sm0ky2]

I think you'll find that the energies involved are the same, less the losses.

not necessarily


Gravity is an acceleration
whereas a pump moves a mass of water at a constant rate


when we think about the deceleration of the water caused by gravity,
working against our pump:
Let us suppose we move the water up 30 meters in one second
gravity works against us for one second.
m / s / s


on the free-fall gravity is working for 3 seconds


we can calculate the math and see that the final velocities are the same
(30 m/s)
the kinetic energies are drastically different


if we move the same volume of water in 3 seconds:
the energy required to do so is closer to the final energy of free-fall


This is why a rocket burns more fuel the longer it takes to leave earth
at higher velocities, it requires less energy to overcome gravitational acceleration


In a situation where the mass is falling for longer than it took to raise it up:


The energies are not inherently the same.
A slower pump uses more energy


in a general sense, most configurations place us on the losing side of that equation,
But assuming that the energies are "the same" is a mistake.
This is not always mathematically evident,
because when we break the system into parts, our equations add up
and we don't notice the problem


if we wanted to point a finger at it:
It is the second "s" in m / s / s

[sm0ky2]

To clarify:


Pump moves water at m/s (constant rate)


If i wanted to perfectly balance gravity:
I would need a rocket (with infinite fuel)
that accelerated at (9.8 ) m/s/s


something to think about:
Why doesnt the current draw on a vertical pump increase with time?


.................................


Thought about it?
It actually DOES! The time is the time for a volume of water to get from point A to point B within the gravitational field.
To test this run the pump horizontally, then again vertically.
If the time is 1 second or less, current draw is consistent.
If the time is greater than 1 second, current draw is scalar
For this reason, a pressure system is preferred for greater heights than 10m
As less energy is required to pressurize the system than to pump at those heights mechanically.


The pressure system (assuming above the ambient) does not experience gravitational acceleration in the way a free falling object does. A column of water will hang in the air expending no additional energy, so long as the pressure in the column is maintained.
This is akin to an object sitting on the ground.
In this manner, pressure and height are proportional.
Like plumbing in the top floor of a skyscraper.


So:
The losses in a pump system are scalar
While the losses in a pressure system are static
(when height is constant)


This difference in energy is the difference between what the water company uses
to fill the tower
Vs
What we get out of it at ground level.
Hydrodynamics, like a Dam.


Remember gravitational acceleration is independent from mass.
Pressure systems, pumps, ballistics, or virtually (almost) any other method
of us moving the water is absolutely dependent upon mass.
more specifically, the density of that mass.


while under pressure, aerated water is far less dense.
Even though the air is compressed and the "amount" of water moved over time hasn't changed significantly, the density of that water has.


Falling momentum, on the other hand, let's say the water were contained in a (massless) vessel
doesn't care about the air


here again we can draw inequality.


Let's think about the momentum itself
as well as the kinetic energy:
in one condition we have a mass in constant motion
On the other we have an accelerating mass
What is different about these two conditions?

[Willy]

Greatings
                frii143

Physics, which Smoky2 and some other users are aware of but.....

It requires the same amount of energy to lift an object against gravity's force
(a same amount of height), 

1. When it is lifted rapidly.
   as
2. When it is lifted slowly.

This does not mean that the mechanism or the method to cause the lifting is as energy
efficient in both circumstances.

The same amount of energy is present in an object's falling due to gravity's force,
(a same amount of height), 

1. When it falls rapidly.
   as
2. When it falls slowly.

It      SEEMS     as if     an object that has fallen rapidly had more energy, than the
same object had, in its being lowered gradually (a same amount of distance).

This is because we witness that energy of the rapid fall, all at once.
For example...  upon it having a sudden  impact.
... ... ... ... ... ... ... ...

It requires the         same amount of energy       to accelerate an object of a given
mass, to some       given speed,         against the reactive force of its tendency to remain
at rest (its own inertia).....

1. When we accelerate that object suddenly to that given speed.
       as
2. When we gradually accelerate that object to that same given speed.
   and also note that
The object  when rapidly accelerated reaches that given speed sooner.
The object when gradually accelerated reaches that given speed in longer period of time.

The object  when rapidly accelerated reaches that given speed in a shorter distance of
travel.
The object when gradually accelerated reaches that given speed in a longer distance
of travel..