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Family dividing question ; What's the answer?

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percs
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There are two chairlifts A and B. They are both the same weight and length. The only difference is that chairlift B travels up 1000 ft while chairlift A is perfectly flat beginning to end. If they are operating at the same power would chairlift B move slower than A?
Dec 29 2016 1:42PM
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TheDoughAbides
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yes
Dec 29 2016 1:43PM
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percs
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TheDoughAbidesyes


this is the side I'm on but my brother and dad think that the half coming down on B will counteract the extra force needed to rise the opposite half
Dec 29 2016 1:47PM
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percs
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I think that more power would be required to make B go as fast as A
Dec 29 2016 1:49PM
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percs
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Anyone have some explanation
Dec 29 2016 2:09PM
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Casey
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Are there people riding it? Other wise it would be the same
Dec 29 2016 2:27PM
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hippystinx
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keithnollthis is the side I'm on but my brother and dad think that the half coming down on B will counteract the extra force needed to rise the opposite half


well considering that the uphill side will usually have 50% extra weight on it because of all the people it is carrying up I think the downward travel of the opposite side will not help power the lift.
Dec 29 2016 2:30PM
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Mingg
Posts: 13977 - Karma: 49,303
keithnollthis is the side I'm on but my brother and dad think that the half coming down on B will counteract the extra force needed to rise the opposite half


Assuming you're talking about a traditional chairlift, no because the added weight on the "up" side will make it go slower.
Dec 29 2016 2:30PM
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percs
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CaseyAre there people riding it? Other wise it would be the same


No one riding it. So you think they will move the same speed if they are operating on the same power?
Dec 29 2016 2:31PM
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Casey
Posts: 7849 - Karma: 24,317
keithnollNo one riding it. So you think they will move the same speed if they are operating on the same power?


Yeah
Dec 29 2016 2:42PM
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percs
Posts: 2280 - Karma: 5,788
It looks like ns is divided too. Any physical explanations? I'm pretty sure B would move slower because of friction?
Dec 29 2016 2:48PM
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Casey
Posts: 7849 - Karma: 24,317
keithnollIt looks like ns is divided too. Any physical explanations? I'm pretty sure B would move slower because of friction?


We can only assume the friction is the same for both chairs, the sloped chair has gravity pushing equally down on both the upward and downward chairs, so no matter how strong gravity is they will be the same.
Dec 29 2016 3:51PM
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.Hugo.
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If empty the same
Dec 29 2016 3:52PM
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Ninskasi
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I would say they move the same speed, especially if its same weight and power.
Dec 29 2016 3:55PM
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percs
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So the vertical gain/gravity had no effect on the power needed to produce the same acceleration?
Dec 29 2016 3:59PM
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cozyco
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keithnollSo the vertical gain/gravity had no effect on the power needed to produce the same acceleration?


exactly! On both sides of the chair lift (up and down) is the same force. Without any additional power input.

Thats why an empty chair lift that is supposed to travel up hill will set itself into a balance when you wont have any breaks. (A flat one obviously too)

tl;dr without energy both chair lifts wouldnt spin -> same energy put additionally in both systems -> will move with the same speed

Did this even make sence lol?
Dec 29 2016 4:59PM
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vandersteeze
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As long as the chairs are empty, both will run at the same speed under the same power, due to the fact that the downhill chairs counteract the uphill chairs

However as soon as the "uphill" side of the chairs are loaded (uphill can be either side of the flat one of course) the one with the 1000 ft gain will require more power
Dec 29 2016 6:15PM
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akt416
Posts: 246 - Karma: 568
vandersteezeAs long as the chairs are empty, both will run at the same speed under the same power, due to the fact that the downhill chairs counteract the uphill chairs

However as soon as the "uphill" side of the chairs are loaded (uphill can be either side of the flat one of course) the one with the 1000 ft gain will require more power


this is the answer
Dec 29 2016 8:37PM
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the_moderaper
Posts: 2465 - Karma: 218
Do the wheels on the towers/bullwheels have more friction on one scenario than the other? I think that may be the case.

The lift that moves uphill also has an extra two towers, one at the top and one at the bottom which are where the cable goes from flat to angled to flat again. Extra wheels / added friction.

Or if the engine driving them is diesel and located at the top of the lift rather than the bottom, then the flat one again will be faster because theres the air is more dense at the bottom of the mountain.

So if you wana be a dick, its the flat one thats faster.
Dec 29 2016 8:57PM
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Lonely
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The will be both be the same. Gravity has the same effect on the chair whether it is at 1000ft or 0ft, given that they are the same weight (the difference in elevation causes a negligible difference).

Now assuming that they travel the same distance, weigh the same amount, and have the same amount of energy input they must take the same amount of time to complete this course.

Of course there are exceptions to this, and many other variables but yeah.
Dec 29 2016 9:09PM
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TheDoughAbides
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Lonely(the difference in elevation causes a negligible difference).


A difference, nonetheless. it would depend on the period of time over which you are observing the two lifts. like Coriolis force in weather events.
Dec 29 2016 10:56PM
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ghoti_hook
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Newton's second law of motion implies f=ma. We are controlling the variable "force" and if we are assuming that the masses are the same, then theoretically, the speed/acceleration should be the same as well.
Dec 29 2016 10:57PM
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Lonely
Posts: 6741 - Karma: 61,665
TheDoughAbidesA difference, nonetheless. it would depend on the period of time over which you are observing the two lifts. like Coriolis force in weather events.


Yes but I believe for the sake of the question that is ignored.

Although I do believe that they Coriolis force would not be applicable, as it only applies to rotating reference frames if I remember correctly. Which wouldn't make sense even if the lift itself was rotating, because the assumed reference frame is static.
Dec 30 2016 12:00AM
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TheDoughAbides
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LonelyYes but I believe for the sake of the question that is ignored.

Although I do believe that they Coriolis force would not be applicable, as it only applies to rotating reference frames if I remember correctly. Which wouldn't make sense even if the lift itself was rotating, because the assumed reference frame is static.


I agree. I only meant that said difference would only be observable over a relatively long period of time in the same way that Coriolis force is only observable in weather events that occur over multiple days. brainfarting for a better example atm :/
Dec 30 2016 12:12AM
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MIHoodlum
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The uphill would be slower due to torque and stress. The flat lift would not have the extra stress on the motor.
Dec 30 2016 2:02AM
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Cotter
Posts: 2546 - Karma: 849
ghoti_hookNewton's second law of motion implies f=ma. We are controlling the variable "force" and if we are assuming that the masses are the same, then theoretically, the speed/acceleration should be the same as well.


This right here. It's simple physics
Dec 30 2016 5:20AM
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Lonely
Posts: 6741 - Karma: 61,665
TheDoughAbidesI agree. I only meant that said difference would only be observable over a relatively long period of time in the same way that Coriolis force is only observable in weather events that occur over multiple days. brainfarting for a better example atm :/


Ahh okay gotcha
Dec 30 2016 10:14AM
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