# Power output from a falling masss over a time period

• jeff jones
In summary: 10ft is 3m. w=fd or for gravitational potential energy w=mgh. Can you do the calculation?Watts = distance times gravity potential times heightDoesn't the controlled fall change the equation by reducing the energy potentialAt best I don't think that sentence means anything.
jeff jones
How did you find PF?: youtube

[Moderator: moved from new member intro forum]How did you find PF?: youtube

i need a falling mass over time /joules per kilo over 1hr time
also need to know how to figure gearing to maintain fall over time in regards to a set resistance such as a 5 kw alternator

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Welcome to PF. This is the New Member Introduction section. It is not for questions.

Your question might fit best at

https://www.physicsforums.com/forums/general-engineering.113/But before posting there, I suggest that you specify the question better. The first question about joules, is that for a free-falling mass? The second question is definitely not free-fall.

Regarding the second question, what are you trying to design, a gravity lighting system perhaps? We can give better answers if we know more. Without knowing anything, I say for the second question to make the fall last longer, lift it higher. I don't think that is what you want.

anorlunda said:
Welcome to PF. This is the New Member Introduction section. It is not for questions.

Your question might fit best at

https://www.physicsforums.com/forums/general-engineering.113/But before posting there, I suggest that you specify the question better. The first question about joules, is that for a free-falling mass? The second question is definitely not free-fall.

Regarding the second question, what are you trying to design, a gravity lighting system perhaps? We can give better answers if we know more. Without knowing anything, I say for the second question to make the fall last longer, lift it higher. I don't think that is what you want.
Consider both questions are related
A gravity light is the best similar concept I can think of
I just need a plug and play formula for a very large mass and gearing for it

Also
I wasn't sure what response was needed in intro
Lol

10 ft
1,000,000 kilos
I would like to use 10 ft per hr as a guide and insert time and value according to given circumstance.

How about 1 million liters of water? That's a lot more practical. You pump the water uphill, then make electricity as it comes down. The round trip efficiency is about 80%. We call it pumped hydro power. For that, 5 kw is pretty small.

https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity

PeroK
jeff jones said:
10 ft
1,000,000 kilos
I would like to use 10 ft per hr as a guide and insert time and value according to given circumstance.
10ft is 3m. w=fd or for gravitational potential energy w=mgh. Can you do the calculation?

anorlunda said:

View attachment 251933

How about 1 million liters of water? That's a lot more practical. You pump the water uphill, then make electricity as it comes down. The round trip efficiency is about 80%. We call it pumped hydro power. For that, 5 kw is pretty small.

https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity
Lol
I understand what you are saying
But
I can't give you all the info w out a non discloser agreement
The numbers I am using are examples and are small compared to actual
As long as we keep derivitives of 10
I should be able to keep the math from getting out of hand
I need to be able to not only understand the joules /weight to watts/time ratio but add and subtract it according to need functionality and whatever other perogitives are needed
Also
I have 10 ft of fall w said weight
Displacing said amount of water over 1 hr
Can I have a formula to show power generated by said water using a micro turbo or even a large turbine if it's possible
The possibilities are unlimited if you have a big enough hammer

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10 ft
1,000,000 kilos
I would like to use 10 ft per hr as a guide and insert time and value according to given circumstance.the sheer mass means I have to use a controlled fall to use the energy
russ_watters said:
10ft is 3m. w=fd or for gravitational potential energy w=mgh. Can you do the calculation?
Watts = distance times gravity potential times height
Doesn't the controlled fall change the equation by reducing the energy potential

jeff jones said:
Watts = distance times gravity potential times height
No it doesn't.
Doesn't the controlled fall change the equation by reducing the energy potential
At best I don't think that sentence means anything.

Can you just try the math I gave you please. And pay attention to the units.

1,000,000 kg
3 meters
g = 9.81 m/s/s
29,430,000joules=29,430kw
29,430 kw /3600=8.175 kw potential
if correct
then
each time i fall i have 8 kw for an hr approx
there are more variables involved in this but this is adequate to start

anorlunda said:

View attachment 251933

How about 1 million liters of water? That's a lot more practical. You pump the water uphill, then make electricity as it comes down. The round trip efficiency is about 80%. We call it pumped hydro power. For that, 5 kw is pretty small.

https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity
i have 1,000,000 kg that will drop 10 ft
10 ft of water can be pushed and pulled equating to 20 ft of water
if said weight was a barge that measured 30x100 and was in a steel chamber so all water can be ran thru a turbo or other form of weight transfer
how can i figure the potential energy in this

jeff jones said:
how can i figure the potential energy in this
It is no different than the calculation you did in #12. kg of water and height in meters.

As I said before, large scale pumped hydro systems achieve 80% efficiency. The energy out is 0.8 times the energy in. As you know, power is related to how fast you put energy in or out.

Are you just curious about the physics, or do you plan to make something?

yes
i am tired of paying for energy and i have access to 1,000,000kg that rise and fall
i would like to use said energy for businesses that are energy hogs and i have access to a flywheel company to store end product and dispense it as needed
its a win win for me
i needed a simple calc to use in a plug and play calc to show the falling mass and water mass energy output for a base wattage guide to build around
it amazes me that the tonnage actually produces so little wattage but it does make sense
i love physics and all things related to science and it saddens me that the younger generation can't see the mystery and depth of it

jeff jones said:
1,000,000 kg
3 meters
g = 9.81 m/s/s
29,430,000joules=29,430kw
29,430 kw /3600=8.175 kw potential
if correct
then
each time i fall i have 8 kw for an hr approx
there are more variables involved in this but this is adequate to start
This is very sloppy with the units. If you are going to spend any time on ideas like this you need to understand the differences between forces, energy, and power.
29,430,000joules=29,430kw
No, 29,430,000 joules is 29,430 kilo Joules
Better to say 29,430,000 joules is 29,430 kilowatt-seconds (because a joule is a watt-second)
then 29,430 kilowatt-seconds divided by 3600 second per hour is 8.175 kilowatt-hours

You came to the right value in the end, but every time you write "kw" when you mean "kw-hr" fewer and fewer people who know what's going on will be paying any attention.

jeff jones said:
Wow. May I ask what that is?

gmax137 said:
You came to the right value in the end, but every time you write "kw" when you mean "kw-hr" fewer and fewer people who know what's going on will be paying any attention.
Indeed, I saw the error and couldn't/didn't bother to figure out where it was really going. Good catch.

jeff jones said:
yes
i am tired of paying for energy and i have access to 1,000,000kg that rise and fall
i would like to use said energy for businesses that are energy hogs and i have access to a flywheel company to store end product and dispense it as needed
its a win win for me
I moved this thread to our DIY forum.

If you are thinking about energy hog businesses, do you know their energy consumption? 8kWh at a price of $0.25/kWh is worth$2. What is the typical electric bill of those businesses you want to help? You can answer in money units, or kWh units.

Good engineering advice is to always know the requirements before starting design. Size, cost, energy requirement, power requirement, hours per day requirement, safety requirement. All those things should be known before you choose the method making electricity.

Nobody would spend 1 million dollars to save $2 per day on their electric bill. You talk about lifting masses, gearing, flywheels, and water, all those choices come after you know your requirements. berkeman and jrmichler russ_watters said: Wow. May I ask what that is? if my end game is maximum wattage then the mass could be any large seagoing vessel on the puget sound and the typical container ship is well over 1 million kilos tide change every 24 hrs varies from 2 to 13 twice every day but using a formula and setting up a real world application sucks jeff jones said: if my end game is maximum wattage then the mass could be any large seagoing vessel on the puget sound and the typical container ship is well over 1 million kilos tide change every 24 hrs varies from 2 to 13 twice every day but using a formula and setting up a real world application sucks To extract energy from that elevated mass, you will need to support it significantly above the waterline during the extraction period. How much do you think that infrastructure will cost you to build? The only other way would be to build locks on the Sound similar to the Panama Canal, and extract energy from the water flowing in and out from the sea during tide changes. But that would impede waterway traffic, which would also be a problem. Hmm... anorlunda said: I moved this thread to our DIY forum. If you are thinking about energy hog businesses, do you know their energy consumption? 8kWh at a price of$0.25/kWh is worth $2. What is the typical electric bill of those businesses you want to help? You can answer in money units, or kWh units. Good engineering advice is to always know the requirements before starting design. Size, cost, energy requirement, power requirement, hours per day requirement, safety requirement. All those things should be known before you choose the method making electricity. Nobody would spend 1 million dollars to save$2 per day on their electric bill.

You talk about lifting masses, gearing, flywheels, and water, all those choices come after you know your requirements.
i am looking at small smelters using induction heating
puget power has special rates for large consumers so i won't qualify so ave is .10/kwh depending on time of day
the flywheel assembly that i mentioned is made by beacon power and will convert any voltage to useable voltage
they are spendy but its a nice set up to keep track of wattage made /used/still available
even if i don't use the power but want to sell it
the power companies will buy it at a reduced rate
or i could sell it to another business as long as i meet the stringent codes and procedures
the cost to raise the mass 10 ft is nothing
its a free energy give away

jeff jones said:
its a free energy give away

berkeman said:
To extract energy from that elevated mass, you will need to support it significantly above the waterline during the extraction period. How much do you think that infrastructure will cost you to build?

The only other way would be to build locks on the Sound similar to the Panama Canal, and extract energy from the water flowing in and out from the sea during tide changes. But that would impede waterway traffic, which would also be a problem.

Hmm...
nope and nope
i am not looking for maximum efficiency
i looked into a linear generator to use the small distance to make the energy and it worked very well with my flywheel setup
building locks in puget sound would result in the mayor of seattle parking his kayak in the middle of it and singing cumbya
even if i had a single large chain tied to a geared drive it would work
not well,but it would work
i can get access to both shoreline and bouy points for minimal dollars
if i had access to a decent designer and a few engineers w a power point and flashy pictures
i will have investors kicking my door in
if i offer green credits
the sky is the limit

lol
do a quick search on the narrows and see what the volume of water is that races thru a very narrow channel
its staggering

berkeman said:
extract energy from the water flowing in and out from the sea during tide changes

That's a great idea. Since the mass of the water exceeds the mass of the ships, why don't we move this to somewhere without so much maritime traffic. We can also increase the efficiency by using a river instead, since then we don't need to worry about both directions. We could call it a...damn! Just slipped my mind. What was I going to call it?

Damn. Damn. Damn!

jrmichler, russ_watters, Bystander and 1 other person
berkeman said:

jeff jones said:
i looked into a linear generator to use the small distance to make the energy and it worked very well with my flywheel setup
To get the weight of the ship to convert to energy as it lowers, you need to support the weight of the ship. Which word do you not understand?

jeff jones said:
even if i had a single large chain tied to a geared drive it would work
And this chain will support the weight of the ship as it is lowered to produce energy?

jeff jones said:
if i had access to a decent designer and a few engineers w a power point and flashy pictures
i will have investors kicking my door in
if i offer green credits
the sky is the limit
Sorry to be blunt, but I think you are delusional. Go ahead and hire an engineer to do a feasibility analysis, and best wishes.

sorry ,the total kwh needed per ton is 650 for al and steel
berkeman said:
To get the weight of the ship to convert to energy as it lowers, you need to support the weight of the ship. Which word do you not understand?And this chain will support the weight of the ship as it is lowered to produce energy?Sorry to be blunt, but I think you are delusional. Go ahead and hire an engineer to do a feasibility analysis, and best wishes.
its alright
i appreciate any and all comments

jeff jones said:
if i had access to a decent designer and a few engineers w a power point and flashy pictures
i will have investors kicking my door in
if i offer green credits
the sky is the limit
Theoretically the idea of tidal power is sound, but it isn't clear how, from a practical perspective, you would like to harness it. Engineers have indeed been working on this issue for a long time, and the practical issues - specifically the low quality of the energy(low head) - tend to make it impractical. Since you acknowledge you need an engineer to develop your idea, it appears likely that you are just unaware that it's probably already been tried and has proven impractical.

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berkeman
That's a great idea. Since the mass of the water exceeds the mass of the ships, why don't we move this to somewhere without so much maritime traffic. We can also increase the efficiency by using a river instead, since then we don't need to worry about both directions. We could call it a...damn! Just slipped my mind. What was I going to call it?

Damn. Damn. Damn!
russ_watters said:
Theoretically the idea of tidal power is sound, but it isn't clear how, from a practical perspective, you would like to harness it. Engineers have indeed been working on this issue for a long time, and the practical issues - specifically the low quality of the energy(low head) - tend to make it impractical. Since you acknowledge you need an engineer to develop your idea, it appears likely that you are just unaware that it's probably already been tried and has proven impractical.
its been proven impractical for general consumption/
i have no need or use for general consumption since i want an on demand power system unlike the standard power system which uses a wasteful way of producing and distributing energy
a tidal generator can produce megawatts of power
yes i am an avid fan of mit lectures of alternate power generators,power transmission past present and future
alternate power storage/thermal batteries/tower weight storage/gravity weight storage /so on so forth ad nauseum
tesla is alive and well and living in the ethorium
i am looking at utilizing a resource that is not utilized at all
yes i am working on the engineering and i have several quotes from engineers to make a set of ready to go plans for a small scalable unit of my design
the 35k price tag for a set of plans to submit to county is a little out of reach
but building a working scale model for less then a 1000 with counties blessing is possible

jeff jones said:
small scalable unit of my design
How did you complete a design without knowledge if the formula you asked about in post #1?

russ_watters
jeff jones said:
its been proven impractical for general consumption/
i have no need or use for general consumption since i want an on demand power system unlike the standard power system which uses a wasteful way of producing and distributing energy
This is almost never true; usually it is more energy, cost, land etc efficient to have centralized, large power stations, even when you account for transmition/distribution loss.
yes i am working on the engineering and i have several quotes from engineers to make a set of ready to go plans for a small scalable unit of my design
the 35k price tag for a set of plans to submit to county is a little out of reach
but building a working scale model for less then a 1000 with counties blessing is possible
Building a working scale model is a good approach. You may also want to consider speaking to a lawyer about patents and IP issues, if you haven't already.

And not for nothing, but you should work on presenting yourself better, specifically with your writing. Even if you don't think we at PF matter enough to be worthy of your best effort, it's good practice and you really never do know when you might be talking to someone who can really help.

Bystander and berkeman
Twenty years ago I was working in coastal Maine, and an older friend showed me an old factory or mill along one of the rivers that, back in its day had had a waterwheel arrangement that turned with the tidal flow thus powering the mill. He had been around as a youngster when the mill was operating, and told me they took lunch at slack tide. There had been an electric light above the wheel that would come back on when the wheel began turning again, signaling "everyone get back inside, lunch break is over."

These things can work, but they do hearken to simpler times when life was lived at a slower pace.

berkeman, russ_watters, DaveE and 1 other person
anorlunda said:
How did you complete a design without knowledge if the formula you asked about in post #1?
I started w wanting to capture tidal change w large masses and small falls
I got hung up on how to transfer enormous weights to a usable form of motion
As I was watching a YouTube video on alternate storage for power I found beacon power
As I didn't have a clear path for transferring motions but I did know that energy can be produced I figured I would see what it would cost to store the power since it's intermittent
They actually called me back while I was working and I sat 40 feet in the air describing what I envision should happen
5 engineers on a teleconference listened to what I had
They said no
Do it this way
This will work way better
I said
Cool
They proceeded to tell me that they can take any voltage and amperage and store it to be drawn out as needed
They also said that a lineal alternator was the way to go
I said
Cool
They then proceeded to tell me that in 2 weeks I can have plans drawn up and since everything is off the shelf it would be fairly easy
I said
Cool
At no point did I ask how much wattage or energy would be made
At that point I cried a little
Gosh darn engineers
The plans cost 35k
The off the shelf items start at 75k
I need a working prototype that cost less than 1000
And is scalable
My brother works on solar farms
If I can sell him on the project w accurate numbers and a small working or even non working but viable prototype
I will get the funding
Now
I have figured out the mass to energy ratio
It will need some mechanical workarounds and possibly 2 or more fixed points
But
It works
And it works well
And I do thank u folks for the assist

@jeff jones , when you finish your prototype and test it, please post here again. Until then, I suggest that face-to-face questions with that panel of five engineers you have on call would be better than asking strangers on PF.

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## 1. How is power output calculated from a falling mass over a time period?

Power output is calculated by multiplying the force of gravity (9.8 m/s²) by the mass of the object (in kilograms) and the vertical distance it falls (in meters) over a given time period (in seconds). The formula for power output is P = mgh/t, where P is power, m is mass, g is gravity, h is height, and t is time.

## 2. What is the relationship between power output and the mass of the falling object?

The power output from a falling mass is directly proportional to the mass of the object. This means that as the mass increases, the power output also increases. This is because a heavier object has more gravitational potential energy and therefore releases more energy as it falls.

## 3. How does the height of the fall affect the power output?

The height of the fall also has a direct impact on the power output. As the height increases, the potential energy of the object also increases, resulting in a higher power output. This is because the object has more distance to accelerate and release energy as it falls.

## 4. Can the power output be increased by changing the time period of the fall?

No, the power output is not affected by the time period of the fall. The formula for power output (P = mgh/t) shows that the time period is in the denominator, meaning it has an inverse relationship with power output. This means that as the time period increases, the power output decreases, and vice versa.

## 5. What are some real-world applications of power output from a falling mass over a time period?

One common application is in hydropower plants, where the potential energy of falling water is converted into mechanical energy to generate electricity. Another application is in roller coasters, where the gravitational potential energy of the coaster at the top of a hill is converted into kinetic energy as it falls, providing a thrilling ride for passengers.

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