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ScienceNostalgia101

Gravity-driven transpotation along a shallow incline

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Posted (edited)

So firefighters, when they need to get to a lower floor in a hurry, slide down a pole. They let gravity to the work, rather than their legs.

 

I'm kind of left wondering; wouldn't this be a good alternative means of transport, to locations of a lower elevation? Rather than having a bunch of asphalt-paved roads leading from something high-elevation (eg. an airport) to something low-elevation (eg. a seaport) why not have; instead of and/or in addition; a pole or large slide that lets gravity do the work?

 

Here are my two proposals.

 

1. A thick metal cylinder, that would be secured on each end, from which customers could put their arms and legs into sleeves attached to rings around the pipe. So long as the force of friction is less than the forward component of gravity pulling them along, would they not reach their destination without the aid of fossil fuels and/or electricity?

 

2. A large ramp whose top surface is of reduced friction; and/or has a cart on which people can sit, as it too slides along the surface. Assume the second sentence from #1 still applies.

 

Assume for the purposes of each of the above that safety precautions; such as guard rails for the latter, or spring-loaded protective clothing for either; are available.

Edited by ScienceNostalgia101

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Your proposal would likely meet its failure at the hands of the lawyers, even if they passed muster with physicists and engineers.

13 minutes ago, ScienceNostalgia101 said:

So firefighters, when they need to get to a lower floor in a hurry, slide down a pole. They let gravity to the work, rather than their legs.

 

I'm kind of left wondering; wouldn't this be a good alternative means of transport, to locations of a lower elevation? Rather than having a bunch of asphalt-paved roads leading from something high-elevation (eg. an airport) to something low-elevation (eg. a seaport) why not have; instead of and/or in addition; a pole or large slide that lets gravity do the work?

 

Here are my two proposals.

 

1. A thick metal cylinder, that would be secured on each end, from which customers could put their arms and legs into sleeves attached to rings around the pipe. So long as the force of friction is less than the forward component of gravity pulling them along, would they not reach their destination without the aid of fossil fuels and/or electricity?

How does this get a car down a hill?

 

13 minutes ago, ScienceNostalgia101 said:

2. A large ramp whose top surface is of reduced friction; and/or has a cart on which people can sit, as it too slides along the surface. Assume the second sentence from #1 still applies.

Same question.

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15 minutes ago, ScienceNostalgia101 said:

I'm kind of left wondering; wouldn't this be a good alternative means of transport, to locations of a lower elevation? Rather than having a bunch of asphalt-paved roads leading from something high-elevation (eg. an airport) to something low-elevation (eg. a seaport) why not have; instead of and/or in addition; a pole or large slide that lets gravity do the work?

Relying on friction probably isn't good enough to ensure a safe and controlled speed of descent.

16 minutes ago, ScienceNostalgia101 said:

2. A large ramp whose top surface is of reduced friction; and/or has a cart on which people can sit, as it too slides along the surface. Assume the second sentence from #1 still applies.

You have to take the cart back up to the top, which would require a source of energy. Also, there is probably limited number of people who only ever want to go downhill so, at some point, you are going to have get the people back up to the top as well.

Now, here's an Idea: why not have two of your carts tied to each other with a cable that goes round a pulley at the top of the hill. The cable is just long enough that when one cart is at the top, the other one is at the bottom, When you have passengers in both carts, you let the one at the top go down and pull the other one up. You may need to use some power to overcome different loads and control the speed, but less than without the counterbalancing cart.

https://en.wikipedia.org/wiki/Funicular

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47 minutes ago, Strange said:

Now, here's an Idea: why not have two of your carts tied to each other with a cable that goes round a pulley at the top of the hill. The cable is just long enough that when one cart is at the top, the other one is at the bottom, When you have passengers in both carts, you let the one at the top go down and pull the other one up. You may need to use some power to overcome different loads and control the speed, but less than without the counterbalancing cart.

https://en.wikipedia.org/wiki/Funicular

Yes a good idea and link, except that your link is short on detail of the hydraulic ones. +1

Here is a link to one such near me

https://en.wikipedia.org/wiki/Lynton_and_Lynmouth_Cliff_Railway

Each car has an underslung tank which is filled with stream water at the top of the cliff and emptied at the bottom.

The view is fantastic as you go up or down.

There are actually quite a few of these.

There is a smaller one on the cliffs of the Severn gorge at Bridgnorth and I went on one on the side of the Rhine gorge a few years back, somewhere near Koblenz.

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For electric cars, regenerative braking helps charge batteries to get the car back up the hill. There's no one size fits all solution.

 

 

Some of this reminds me of all the proposals I was seeing in the newspaper, after 9/11.

The issue of how to get many people quickly down and out of tall buildings.

Don't know if any of the ideas ever got implemented.

 

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Posted (edited)
6 hours ago, ScienceNostalgia101 said:

So firefighters, when they need to get to a lower floor in a hurry, slide down a pole. They let gravity to the work, rather than their legs.

 

I'm kind of left wondering; wouldn't this be a good alternative means of transport, to locations of a lower elevation? Rather than having a bunch of asphalt-paved roads leading from something high-elevation (eg. an airport) to something low-elevation (eg. a seaport) why not have; instead of and/or in addition; a pole or large slide that lets gravity do the work?

 

Here are my two proposals.

 

1. A thick metal cylinder, that would be secured on each end, from which customers could put their arms and legs into sleeves attached to rings around the pipe. So long as the force of friction is less than the forward component of gravity pulling them along, would they not reach their destination without the aid of fossil fuels and/or electricity?

 

2. A large ramp whose top surface is of reduced friction; and/or has a cart on which people can sit, as it too slides along the surface. Assume the second sentence from #1 still applies.

 

Assume for the purposes of each of the above that safety precautions; such as guard rails for the latter, or spring-loaded protective clothing for either; are available.

For long distances, there is a hypothetical means of travel known as the "gravity train".

Basic concept is this:  You start by digging a tunnel with a downward slope.  You keep digging in a straight line.  Since the Earth's surface is curved, your straight line tunnel will end up coming out at some other point of the Earth's surface.  The midpoint of the tunnel will be closer to the center of the Earth and thus lower than the ends.

You seal and evacuate the tunnel of air and put a mag-lev train in it.  If you start the train at on end, it will slide down the tunnel picking up speed until it reaches the mid point, and then will climb back up the other side, coming to a stop at the other end.  Now here's the kicker:  No matter how far apart the ends of the tunnel are from each other, the trip will take a bit over 42 min.

Of course, you would never be able to eliminate all friction and losses, so you would have to add a bit of energy to get the train to reach all the way to the other end.  Also, the further apart the ends, the deeper the depth of the midpoint, so there would be practical limits on just how long you could make the tunnel.

It's a neat idea, even if it never becomes practical.

 

Edited by Janus

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