here's one for ya

[brett friggin favre]

just took a test, and we had to solve this:

a guy's eating a salad on his balcony and unknowingly drips a drop of olive oil onto a pizza delivery man below, who sues for $10m because he claims the olive oil burned his scalp. prove that this is not possible

we were told to ignore heat loss to the air while falling, heat gain due to friction, and were not given a starting temperature or the temperature needed to burn the human scalp. we were given the specific heat of the oil as 1.97 kj/kg*°K.

this is an introduction to mechanical engineering course. i repeat, INTRODUCTION. the prof used to teach thermodynamics at MIT. now if i was in thermodynamics at MIT i bet i could figure this out, but for an INTRO TO FUCKING MECHANICAL ENGINEERING COURSE i think this is a bit absurd.

[Penis シ]

A few things. 1. Why does he have hot olive oil on a salad? That's gross. 2. Why is he ordering pizza if he has a salad? That's just gluttonous. 3. Why is he eating salad OVER his balcony? That's just stupid. 4. Even if he is dumb enough, why is the bowl far out enough that he can drip on the way to his mouth while leaning out? That's just silly.

Please speak with your asshole professor and answer these for me.

[brett friggin favre]

A few things. 1. Why does he have hot olive oil on a salad? That's gross. 2. Why is he ordering pizza if he has a salad? That's just gluttonous. 3. Why is he eating salad OVER his balcony? That's just stupid. 4. Even if he is dumb enough, why is the bowl far out enough that he can drip on the way to his mouth while leaning out? That's just silly.

Please speak with your asshole professor and answer these for me.

i wrote him a little note saying "i have no idea what you want. you want me to prove that, ignoring many heating factors, olive oil could not rise from an unknown temperature to another unknown temperature. so i'm gonna say no, the sun can't heat up olive oil however much that is. and why the hell does it matter that it reaches 200 km/h while it falls if we're supposed to ignore frictional heating with the air? why the hell does it matter whether or not it splattered when it hit his hat because i wouldn't know what it splattering would even mean because you never even discussed any of this with us, and neither did the book."

[SCRIBBLE]

just took a test, and we had to solve this:

a guy's eating a salad on his balcony and unknowingly drips a drop of olive oil onto a pizza delivery man below, who sues for $10m because he claims the olive oil burned his scalp. prove that this is not possible

we were told to ignore heat loss to the air while falling, heat gain due to friction, and were not given a starting temperature or the temperature needed to burn the human scalp. we were given the specific heat of the oil as 1.97 kj/kg*°K.

this is an introduction to mechanical engineering course. i repeat, INTRODUCTION. the prof used to teach thermodynamics at MIT. now if i was in thermodynamics at MIT i bet i could figure this out, but for an INTRO TO FUCKING MECHANICAL ENGINEERING COURSE i think this is a bit absurd.

first thing i would note is that it would technically be a scald as opposed to a burn. also to prove the oil was not hot enough to burn his scalp all you have to do is remember hot oil and water does not mix -- therefore if the oil was on the salad (vegetables made up primarily of water) and was hot enough to burn someone it would have reacted violently with the water in the salad. hot oil has a higher temperature than that of steam so when the hot oil hits the water, steam is created and expands violently. so the proof lies in the fact that the salad wasn't wilted and steam wasn't shooting out of the bowl.

hot oil is also less viscous than oil at room temperature and would probably separate to the point of a spray due to turbulence created by the air while falling if the oil was hot.

intro to thermodynamics man... that was an easy question though an MIT professor should have known the difference between a scald and a burn.


A few things. 1. Why does he have hot olive oil on a salad? That's gross. 2. Why is he ordering pizza if he has a salad? That's just gluttonous. 3. Why is he eating salad OVER his balcony? That's just stupid. 4. Even if he is dumb enough, why is the bowl far out enough that he can drip on the way to his mouth while leaning out? That's just silly.

Please speak with your asshole professor and answer these for me.

1. subjective
2. not stated that he ordered a pizza at all
3. it was stated he was eating it on the balcony, not over
4. again, subjective, all people do not eat the same

[brett friggin favre]

it's not an intro to thermodynamics though. we use different course terminology here but it's essentially ME 101.

[Andrew_Pavlik]

Did you ever find out the answer? It seems more of a riddle then an ME question. Even if you could add the heat due to friction, just plain olive oil couldn't heat up enough from friction to burn someone, well not from the height that it would drop. Also he never gave you the height of the eater there for obviously it had nothing to do with how far it travels.

I mean olive oil can burn, well be used for lamps and such, but you'd have to get it pretty hot. So I guess it's pretty easy to prove it's not possible, oils burn around something like ~350'C so you could say that in order for the oil to burn, it would have been at temps much higher then to cause a burn also it would have been on fire unlike a boiling drop of water.

[brett friggin favre]

Did you ever find out the answer? It seems more of a riddle then an ME question. Even if you could add the heat due to friction, just plain olive oil couldn't heat up enough from friction to burn someone, well not from the height that it would drop. Also he never gave you the height of the eater there for obviously it had nothing to do with how far it travels.

I mean olive oil can burn, well be used for lamps and such, but you'd have to get it pretty hot. So I guess it's pretty easy to prove it's not possible, oils burn around something like ~350'C so you could say that in order for the oil to burn, it would have been at temps much higher then to cause a burn also it would have been on fire unlike a boiling drop of water.

nope, never found the answer. all i can think is maybe he wanted us to assume it started super hot, so hot that it would be impossible and as you said, would combust. but that part was unclear and unless told otherwise, i'm gonna assume this guy didn't get his olive oil from his personal star microwave so it'd be hot enough for it to happen. i'm gonna assume it started at room temp because that's what people do. it's practical. it's engineering. and EVEN IF we assume it started super hot and somehow didn't combust or turn to vapor, and that it'd be cooling down as it decended, we're still not given how hot it had to be to burn the guy or how long it fell. he tells us it falls long enough to reach its terminal velocity of 200 kph, but doesn't say how long it fell at that speed or how high the balcony was. we also don't have the mass of the droplet, nor the surface area.

[Penis シ]

A little googling. Turns out that's pretty cold.
http://www.engineeringtoolbox.com/water-thermal-properties-d_162.html

Granted that's with water and not oil.

[SCRIBBLE]

just took a test, and we had to solve this:

a guy's eating a salad on his balcony and unknowingly drips a drop of olive oil onto a pizza delivery man below, who sues for $10m because he claims the olive oil burned his scalp. prove that this is not possible

we were told to ignore heat loss to the air while falling, heat gain due to friction, and were not given a starting temperature or the temperature needed to burn the human scalp. we were given the specific heat of the oil as 1.97 kj/kg*°K.

this is an introduction to mechanical engineering course. i repeat, INTRODUCTION. the prof used to teach thermodynamics at MIT. now if i was in thermodynamics at MIT i bet i could figure this out, but for an INTRO TO FUCKING MECHANICAL ENGINEERING COURSE i think this is a bit absurd.

Woops, I put too much thought into this one. He's eating a salad so, if the oil is so hot that it would burn a scalp, it would burn his tongue. How to prove it's not possible? Look at his tongue.

[brett friggin favre]

Woops, I put too much thought into this one. He's eating a salad so, if the oil is so hot that it would burn a scalp, it would burn his tongue. How to prove it's not possible? Look at his tongue.

that'd be the answer if it were a riddle, as mentioned above. but he wanted equations and stuff. if only...

[acolyte_to_jippity]

that'd be the answer if it were a riddle, as mentioned above. but he wanted equations and stuff. if only...

mechanical engineering.

assume that it's on the second floor, so about 10 feet, approximate to 3 meters.

now, we know the distance (roughly) the oil would drop, therefore we can calculate the kinetic energy it will have at contact with ground. factoring that into the known specific heat of oil, and extrapolating that value for a single gram (not kilogram) you can figure out exactly how much of a heat gain the oil experienced. now, since this will be a very small number, and since it is a logical assumption that:
A) the delivery man is taller than 0 cm in height
and
B) the oil drop was less than 1 gram
you can infer that the heat gain you calculated is too high, and since it will be very very low anyway, the oil would not gain enough heat to cause harm.

[brett friggin favre]

mechanical engineering.

assume that it's on the second floor, so about 10 feet, approximate to 3 meters.

now, we know the distance (roughly) the oil would drop, therefore we can calculate the kinetic energy it will have at contact with ground. factoring that into the known specific heat of oil, and extrapolating that value for a single gram (not kilogram) you can figure out exactly how much of a heat gain the oil experienced. now, since this will be a very small number, and since it is a logical assumption that:
A) the delivery man is taller than 0 cm in height
and
B) the oil drop was less than 1 gram
you can infer that the heat gain you calculated is too high, and since it will be very very low anyway, the oil would not gain enough heat to cause harm.

it wouldnt reach the velocity of 200 kph in a 2 story drop, and that uses no equations. yes it's logical, but my complaint is that he wanted us to use equations with numbers to prove it mathematically.

[Nemesis]

No it would not burn him. If he's eating a salad you have to mix the olive oil with vinegar for the dressing. if you heat vinegar you destroy the yeast in it and you cant eat it.

Unless the man eating salad was black. if he was then yes, it would be all his fault.

[ZERO]

just took a test, and we had to solve this:

a guy's eating a salad on his balcony and unknowingly drips a drop of olive oil onto a pizza delivery man below, who sues for $10m because he claims the olive oil burned his scalp. prove that this is not possible

we were told to ignore heat loss to the air while falling, heat gain due to friction, and were not given a starting temperature or the temperature needed to burn the human scalp. we were given the specific heat of the oil as 1.97 kj/kg*°K.

this is an introduction to mechanical engineering course. i repeat, INTRODUCTION. the prof used to teach thermodynamics at MIT. now if i was in thermodynamics at MIT i bet i could figure this out, but for an INTRO TO FUCKING MECHANICAL ENGINEERING COURSE i think this is a bit absurd.

It is not possible becuase any judge would have reduced the amount prior to the case. Therefore it is not possible to sue for $10m. A little more legal knowledge makes this much faster to solve.

Also it is not possible becuase olive oil is used as a hair treatment which works as a conditioner so if anything the delivery man would have a healthier scalp as a result of this.

[ZERO]

Ek = ½ mv2

200KPH = 55.5m/s

m=1g or .001kg

so
.5(.001)55.5^2= 1.540125J

1 joule is equal to 0.000526565076466 celsius

so

1.540125*0.000526565076466= 0.0008109760383921982C

Therefore the maximum amount the scalp could have been increased in temp above it's existing ambient is 0.0008109760383921982C and that assumes that all the kinetic force was converted to heat.

Note that you should also be able to calculate the mass exactly becuase you have the terminal velocity.

Actually lets solve b/c he said to ignore drag and other things which leave us with:
sqrt(2mg)=V

So 55.5=sqrt(2m9.8) or 3080.25/19.6=m or 157.1556Kg wait a second...

Either my math is wrong or his claim that the object was moving at 200KPH is wrong or it is not a drop. The question is wrong b/c the conditions of the question create a logical conflict. He forgot I think to calculate in that he said not to factor any resistance of the object falling. This would therefore change what he needs to report as the terminal velocity as it will be different depending on the object. Still though you can do a new calculation even with a 157Kg "drop" and show it can not generate enough heat above ambient.

[taz1stP]

No it would not burn him. If he's eating a salad you have to mix the olive oil with vinegar for the dressing. if you heat vinegar you destroy the yeast in it and you cant eat it.

Unless the man eating salad was black. if he was then yes, it would be all his fault.

cant be a black person who was eatting it just hit a black guy so it was racist if they said it wasn't his fault.

[SCRIBBLE]

cant be a black person who was eatting it just hit a black guy so it was racist if they said it wasn't his fault.

This is a typical Cyber post, which on average is longer than a PhD dissertation, condensed into one patchy, ignorant statement. You two (cyber and taz) crack me up. :lmao:

[Fluffy Frufflebottoms]

It's impossible because there's no such thing as degrees Kelvin.

[brett friggin favre]

It's impossible because there's no such thing as degrees Kelvin.

clever. disregard the word "degrees" you overly proper son of a bitch :coffee:

[ZERO]

Uhm, i solved the problem and also proved the question was flawed in its premise so why no e-cookie yet?

[Steamer]

http://s3.amazonaws.com/gmi-digital-library/83476166-8e88-44e9-83cb-45de42cefe89.jpg

[CYBER]

This is a typical Cyber post, which on average is longer than a PhD dissertation, condensed into one patchy, ignorant statement. You two (cyber and taz) crack me up. :lmao:

hey fuck you! lol...
i just make sure im thourough bcos i hate being called for to explain a point or issue or problem after i make my post.
plus, it helps me filter out the flamers bcos lets face it, unless u;re rly dedicated, you would never read my goddamn posts :)
its a win in my book.

[Carmichal]

Why would someone eat scolding hot oil... I'm not a science major but doesn't stuff tend to cool off after it was taken away from the source of heat... Also water has a fairly high specific heat ( 4.187 kj/kgK) so its much harder to change its temp. Oil is not so much, so i am assumeing when it is taken away from heat it cools off reasonably fast, so why would anyone ever want to take a bite of super hot oil.
I am not a science major and I Don't even have to take a chem class. So I might be an idiot but hey it's fun so why not.

But I think you are all over thinking it.... Why would anyone eat scolding hot oil? Also who heats up oil for a salad?

[christopher]

olive oil is not a great liquid phase heat transfer fluid. it has a high specific heat index greater than other normal and approximately equivalent molecular compounds.


it also has a very high viscosity ratio (compared to water and other oils), thus it is a greatly inefficient transfer fluid.


it's film coefficient is pretty low.



what does this mean? you'd need a lot of oil and a lot of time to transfer 50% of the heat of the oil to the scalp.



i'd use the film coefficient formula to explain how it'd be impossible to burn from just one drop.