Lucas Ford

55 posts

Lucas Ford

Lucas Ford

@LucasCFord

PhD Student at NC State University | interests include energy, climate, water, our planet, and education

Raleigh, NC Katılım Kasım 2020
55 Takip Edilen17 Takipçiler
Lucas Ford retweetledi
ARCHIVED - NASA Climate
ARCHIVED - NASA Climate@NASAClimate·
Don’t like graphs? This new visualization shows monthly global temperature anomalies (changes from an average) between 1880 and 2021, based on @NASAGISS data. White and blue = cooler temps Orange and red = warmer temps More: climate.nasa.gov/climate_resour…
English
35
644
1.5K
0
Lucas Ford
Lucas Ford@LucasCFord·
@quintic @engineers_feed I would argue that because I have control over the orientation (as I am the one trying to time something) that there is no need for an extra property. I can simply control for that by laying the rope flat. Additionally, that would be an experimental property, not a rope property
English
0
0
0
0
Nick Hobson
Nick Hobson@quintic·
@LucasCFord @engineers_feed I think (not 100% sure) the strands could serve to carry part of the flame forward, thereby slightly increasing the burn rate. It would obviously be good to get experimental confirmation! Rope orientation affecting burn rate is an example of why an extra rope property is needed!
English
1
0
0
0
World of Engineering
World of Engineering@engineers_feed·
WoE Quiz: You have 2 pieces of rope, each burns from end to end in 30 minutes. If the two pieces touch, the flame will transfer from one to the other. You cannot assume any properties of the rope that were not stated. Given only 1 match, can you use the ropes to time 45 minutes?
English
188
40
506
0
Lucas Ford
Lucas Ford@LucasCFord·
@quintic @engineers_feed The strands cannot add energy. If their tip is close enough to the rope to carry flame to it, then in the opposite direction the rope would similarly ignite the tip, giving equal burn time. I'm not placing ropes vertically, everything is on the ground.
English
1
0
0
0
Nick Hobson
Nick Hobson@quintic·
@LucasCFord @engineers_feed In one direction, the strands would carry some flame into the body of the rope. In the other, just the strands would burn out. Or... Take an ordinary rope placed on an inverted-V mound. You'd expect it to burn a bit faster upward, and thus burn out faster when lit at both ends.
English
1
0
0
0
Lucas Ford
Lucas Ford@LucasCFord·
@quintic @engineers_feed Your example relys on the assumption that the rope can burn at different rates in different directions. I am convinced that is not possible. The strand example does not work because if the strands are close enough to make the fire faster that would happen in both directions.
English
1
0
0
0
Nick Hobson
Nick Hobson@quintic·
@LucasCFord @engineers_feed But you could take two such identical ropes and join them, as in my example earlier - join AX and BX at X: twitter.com/quintic/status… Then, the stated properties of the rope hold, but the rope can burn slower when lit at both ends. (Or faster, if you join A to B, in that example.)
Nick Hobson@quintic

@LucasCFord @engineers_feed Consider rope AB. Igniting end A, the flame reaches X after 20 mins, and end B after a further 10 mins. Alternatively, igniting end B, the flame reaches X after 20 mins, and end A after a further 10 mins. So it burns either end to end in 30 mins How long if you ignite both ends?

English
1
0
0
0
Lucas Ford
Lucas Ford@LucasCFord·
@quintic @engineers_feed By that logic, the rope would burn at different rates from end to end depending on which side was lit first, which would violate the stated properties of the rope.
English
1
0
0
0
Nick Hobson
Nick Hobson@quintic·
@LucasCFord @engineers_feed The strands could ignite and add to the fire, more so in 1 direction, leading to a slightly faster burn rate in 1 direction. Physically, I'm not convinced all sections of a very irregular rope would burn at the same rate in both directions. Logically, it's an unstated property.
English
1
0
0
0
Lucas Ford
Lucas Ford@LucasCFord·
@quintic @engineers_feed If it was a thin to thick rope, the thin part would burn faster than the thick, but that would occur in both directions. Either way you would get the same time. The directionality of strands does not matter as they begin to burn from their base, which is the rope.
English
1
0
0
0
Nick Hobson
Nick Hobson@quintic·
@LucasCFord @engineers_feed Are you sure about that? I get your point about equal mass, but would a thin to thick rope burn at exactly the same rate as a thick to thin rope? What if the rope had loose strands sticking out in one direction only? I'd say we're assuming a property of the rope not stated.
English
1
0
0
0
Lucas Ford
Lucas Ford@LucasCFord·
@quintic @engineers_feed For the purposes of this brain teaser, I am confident that the same section of rope will burn at the same rate from either direction. Irregular construction or not, you still have the exact same mass that needs to be burnt.
English
1
0
0
0
Nick Hobson
Nick Hobson@quintic·
@LucasCFord @engineers_feed Are you sure that an irregularly constructed rope - maybe of dramatically varying thicknesses along its length - would burn at exactly the same rate in either direction? I'm not! Maybe not as big a difference as 10 vs 20 minutes, but a small discrepancy seems quite likely.
English
1
0
0
0
Lucas Ford
Lucas Ford@LucasCFord·
@quintic @engineers_feed However, if X is in a different location for each scenario then it would take 15 minutes to burn the rope and the flames would meet somewhere in the 20 minute section.
English
1
0
0
0
Lucas Ford
Lucas Ford@LucasCFord·
@quintic @engineers_feed If X is the same place on the rope in both scenarios then what you have described is not possible. If X to B takes 10 minutes for a given rope then B to X must also take 10 minutes, otherwise you have a different rope with different properties.
English
2
0
0
0
Lucas Ford
Lucas Ford@LucasCFord·
@quintic @engineers_feed What property? The only property needed is that the rope burns end to end in 30 mins. Regardless of "how" that rope gets to 30 mins, if you light both ends it will burn in 15 minutes. The flames may not meet in the center if it burns unevenly, but it will burn for 15 minutes.
English
1
0
0
0
Lucas Ford
Lucas Ford@LucasCFord·
@quintic @engineers_feed Since it burns end to end in 30 minutes (only lighting one end), regardless of how quick each portion burns, when you light both ends, the flames will meet (and the rope will be done burning) in half that time.
English
2
0
0
0
Lucas Ford retweetledi
FiveThirtyEight
FiveThirtyEight@FiveThirtyEight·
North Carolina Republicans passed a heavily skewed congressional map. How will the courts respond? 53eig.ht/3ok6Z82
English
3
6
15
0
Lucas Ford retweetledi
Bill Gates
Bill Gates@BillGates·
This week, any college or university student anywhere in the world can download my book How to Avoid a Climate Disaster for free. gatesnot.es/3CeAZYU
English
0
1.4K
6.5K
0
Lucas Ford retweetledi
NC State Football
NC State Football@PackFootball·
FINAL SCORE! WOLFPACK WINS! #HTT
NC State Football tweet media
English
35
809
2.8K
0
Lucas Ford retweetledi
Student Energy Club
Student Energy Club@SENC_NCState·
How does the U.S. electricity grid work, and where are we headed? Join NC State energy researchers @Aditya27k and @LucasCFord for this 101 webinar. Sept. 28th, 3-4:30pm. No math/engineering background needed! Register here: bit.ly/3tO2K6Y
Student Energy Club tweet media
English
0
3
5
0

Keşfet

@quintic @engineers_feed @elonmusk @BarackObama @taylorswift13 @cristiano @BillGates @NASA