[sciencegirl]

Alecifel, thank you for entertaining my idea. You certainly seem to know alot about the subect, and you looked at my idea without sarcasm and I thank you for that.

Even if it doesn't save you much energy, I think the idea can be improved upon. Like a pulley system to hoist the craft. Solar panels to power a super small engine. A sail if wind conditions are right. A bicycle pedal system if you are in a hurry.

As far as feasablity, it would take to many resources to construct. In light of peak oil probably the best thing to do is have everyone use mass transit until we have a workable alternative energy source. I don't think this will happen until the price of fuel triples, but by then it may be to late.

This is my last post here until tomorrow.

[alecifel]

Given the recent spats of deaths by ppl with heart conditions on gravity rides, I'm thinking more on the freight end than anything else... be sure to pack that FedEx box with extra foamnuts!!!!

[Pops]

[s]A cable car uses an external power source to move the cable.

The only power source here is the energy expended by our fingers to talk to our science-girl – who, btw, does not have any concept of science.

See; I just added a few negative calories to her equation.

Calories that we all could use to practice the obvious solution to the problem at hand…

How to walk from here to there.[/s]

Never mind.

[sciencegirl]

go to hell. I am a chemistry major, I am weak in physics, you would know that if you even bothered to read the thread pops. Why don't you try contributing something useful instead of putting people down. I certainly don't deserve that kind of treatment. I demand you apologize at once.

[Omnium]

$this->bbcode_second_pass_quote('sciencegirl', 'g')o to hell. I am a chemistry major, I am weak in physics, you would know that if you even bothered to read the thread pops. Why don't you try contributing something useful instead of putting people down. I certainly don't deserve that kind of treatment. I demand you apologize at once.

[Omnium]

And don't forget technologies such as
nano-solar.

http://www.nanosolar.com/

Google even supports it so it must be good.

[da23]

hmm ... i smell ailrickson

[rogerhb]

$this->bbcode_second_pass_quote('sciencegirl', 'I') am a chemistry major, I am weak in physics.

[peaker_2005]

$this->bbcode_second_pass_quote('rogerhb', '')$this->bbcode_second_pass_quote('sciencegirl', 'I') am a chemistry major, I am weak in physics.

[Lighthouse]

Wasn't the original San Francisco Cable Car driven by a gravity supported system?

In I856, Hallidie built a ditch and flume for a quartz mill, situated at American Bar, two miles above Gray Eagle Bar. The mine was on a hillside eleven hundred feet above the mill. The rock was delivered to the mill in car running by force of gravity. The loaded cars in descending brought up the "empties" for refilling.

Source: http://www.sfmuseum.org/bio/hallidie.html

[Pops]

$this->bbcode_second_pass_quote('Lighthouse', 'W')asn't the original San Francisco Cable Car driven by a gravity supported system?

[PolestaR]

By my rough estimates it takes 7 Calories to climb a 30m high ladder if youre 90kg ... you can walk slowly (3.2kph) 100metres with that same amount of energy over 2 minutes.

If anything it may be a faster mode of travel in some instances and use less energy than some methods of travel.

[Lighthouse]

$this->bbcode_second_pass_quote('Pops', 'W')ell, American Bar is about 120 miles away and separated by the central valley from San Francisco and that quote had nothing to do with cable cars..

[Pops]

I misunderstood your point, lighthouse. I misinterpreted "supported" as "powered" instead of "assisted".

I should have read closer, that was the best citation on this thread.

[azreal60]

Incidently, I highly doubt anyone minds using this forum as a personal brainstorming session.

There is no such thing as thinking too much. There are already plenty of people thinking too little to make up for you...

[BlisteredWhippet]

I've figured it out.

Okay, since nobody wants to climb, lets let gravity do all the work.


Think Cirque du Soleil trapeze high-wire act.

Imagine a queue line at the bottom of the pole. First person has to get up by some conventional method. Now, the only thing is, in order for the system to work, someone must be waiting to go up next.

Only the first person has to climb (be hoisted, whatever) to the top. For the first 300 or so feet of his drop, imagine a tether connected to him which pulls up the next person in queue up as his weight drops (usnig pulleys or some shit). After x amount of feet, the tether disconnects- x being the distance required to pull the next passenger up to the top.

Next guy tethers up, jumps aboard... etc.

Wash, rinse, repeat.

Now imagine the entire setup has two channels (upstream and downstream). So we can really get some circularity. And safety nets.

BTW, I have some experience in ziplines. The common failure point was always the line/vehicle interface. When I was a kid we'd tie rope from the second story deck to the fence and ride down holding onto a piece of PVC pipe. Eventually the rop would burn through the pipe.

Fast forward to college, with steel-braided line and harness to ball-bearing pulley. Man that thing was super fast. I think it took about 150 continuous runs over one drunken party before the pulley heated up enough to cause bearing failure.

Mag-lev line? Then the problem is air braking. How do you STOP? Hit a huge air pillow downstream and tumble down an aircraft-style escape chute?

I would definitely pay a $1 for this kind of fun.

[sciencegirl]

The problem itself is not aways a matter of eneregy. Yes it does cost energy to climb up before you slide down the cable, but which method would get you there quicker, walking 10 kilometers or climbing a 150 meters and gliding 10 kilometers. You can also argue that you could just drive there, but driving a car takes alot of petro energy. Would a gravity cable car use more energy or less energy than a car, and how much. Could you eliminate energy use all together by using alternative energy with a gravity cable car, like solar. (Even wind power if the cable car is high enough off the ground)

The point is that their are alot of things you can try, but you don't know how viable they can be until you try. As for taking math and physics, I have taken some coarses (the required ones) and I passed them, but math was never my thing, I plain stink at most of it, though I have know trouble with chemical equations.

[Niagara]

Sciencegirl, I did some kinematics on your cable car. At first I guessed the ride would be slow and boring because the acceleration would be very small. Was I surprised! Let's ignore rolling friction and wind resistance.

Assuming a 150m drop over 10km, the acceleration would be the sine of the downslope * g (9.8m/s/s)
(for small angles sin theta = tan theta)

a=(150/10000) * 9.8
=.15 m/s/s ; the acceleration of the tram

using d=.5at^2

t=sqr(2d/a)
=sqr(2*10000/.15)
=365 seconds

i.e., the 10km trip will take only 6 minutes. That's cool! Much faster than out local bus transit

Now, let's look at the final velocity on arrival at the tram station.

v^2 = 2*a*d
or
v=sqr(2*a*d)
=sqr(2*.15*10000)
=54 m/s

Cool! We arrive at a screaming 200km/h

I love it. Sign me up for a commuter pass on your tram!

[sciencegirl]

Wow, your good at math. Thanx for the calculations. I never imagined it would be such a speedy trip. It probably would have taken 5 hours had i walked the 10 kilometers. There would still be the matter of raising the craft back up for the return trip, but I am sure that a couple of pulleys could manage that easily enough.

[Falconoffury]

I think some posters here are being unfair to this idea and the person suggesting it. I don't think anyone here said that this would be a solution to anything. I see it as simply an interesting mode of transport.

The easiest way to increase the efficiency of such a device would be to decrease the weight of the vehicle which is attached to the cable. I imagine that a chair with a seatbelt and part to attach to the cable could accomplish the task. If I were to carry a 25 pound chair up 100 meters of stairs to get myself 10 miles, that sounds like it would be worth it. It would be kind of like a one man rollercoaster.