How to optimally transfer potential energy from a large mass to accelerate a small one upwards.

[Fernando137]

With the potential energy of a large mass (for example 50 kg at 10 meters high) I want to accelerate a smaller mass (5-25 kg) upwards. I see that simple mechanisms like pulleys, levers, and simple gears leave a lot of kinetic energy in the large mass when it reaches the ground.
Is there some clever mechanism that optimally transfers the energy to the small one? Ideally with some combination of levers and/or gears. (Hydraulic or Pneumatic as a last option)

 

[Compositepro]

Use the mass to tension a cable that accelerates your smaller mass like a bow string does to an arrow.

 

[drawoh]

With the potential energy of a large mass (for example 50 kg at 10 meters high) I want to accelerate a smaller mass (5-25 kg) upwards. I see that simple mechanisms like pulleys, levers, and simple gears leave a lot of kinetic energy in the large mass when it reaches the ground.

How fast should the 5-25kg mass accelerate, and what speed should it wind up at.

Your potential energy is weight times elevation. Your 50kg mass weighs around 500N. Your smaller mass will wind up with kinetic energy, which is mass times velocity squared divided by two.

 

[3DDave]

Trebuchets - The Hurl - Wiki

thehurl.wikidot.com

 

[Fernando137]

Trebuchets - The Hurl - Wiki

thehurl.wikidot.com

Aha, nice page. With some of those trebuchet variants it seems like they are trying to optimize what I was saying.
Although some machines will be difficult to analyze

 

[Fernando137]

Thanks everyone. I actually had some errors in the spreadsheet that underestimated the potential energy transfer. Fixed it for now.

Merry Christmas and Happy New Year.

 

[human909]

Trebuchets - The Hurl - Wiki

thehurl.wikidot.com

Ah! The original "engineers"!

"The term engineering itself has a much more recent etymology, deriving from the word engineer, which itself dates back to 1325, when an engine’er (literally, one who operates an engine) originally referred to "a constructor of military engines."[1] In this context, now obsolete, an "engine" referred to a military machine, i. e., a mechanical contraption used in war (for example, a catapult)."
-Source: https://en.wikipedia.org/wiki/History_of_engineering

Going back to the original meaning of the word engineers also explains why civil engineers are call that, because it originated as a distinguishing term from MILITARY engineers.

 

[Snickster]

I don't know how you would create a practical machine to do this but if you drop a weight from a height onto a spring sized for the forces and energy involved it will compress until all of the kinetic energy is used up into compression of the spring. Then when the spring is compressed to a point where the mass comes to rest a locking mechanism latches the spring in the compressed condition. Then the energy of the compressed spring is somehow transferred to the smaller mass. This could be by placing the smaller mass on the spring after removing the larger mass or by mechanical mechanisms such as levers, gears, pulleys, etc. This will theoretically capture all of the initial potential energy of the larger mass that was converted into kinetic energy.

 

[rb1957]

billards anyone ? freeze the cue ball on the target to maximise the energy transfer ...

 

[LittleInch]

Or you need aome sort of mechanism using some sort of cone or spiral wire guide so that the as the heavy weight slows down, the lighter weight goes faster and faster.

Don you want constant acceleration or just to go faster?