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StillLivin (original poster member #40229) posted at 4:58 AM on Friday, October 5th, 2018
I sick at word problems and functions. Combine the two and forget it. Anyone want to point me in the right direction?
The problem is: An accident at an oil drilling platform is causing a circular-shaped oil slick to form. The volume of the oil slick is roughly given by V(r)= 0.08 x pi x r(squared), where r is the radius of the slick in feet. In turn, the radius is increasing over time according to the function r(t) = 0.5t, where t is measured in minutes. Find (V of r)(t), and give a practical interpretation of what this function tells you. After how many minutes will the volume of the slick be 225 cubic feet?
Any takers? All I know is the volume formula. 🤷♀️
"Bitch please a good man can't be stolen." ROFLMAO - SBB: 7/2/2014
still-living ( member #30434) posted at 12:11 PM on Friday, October 5th, 2018
I'm not a math major but I will attempt to help.
Assume 0.08 is in feet.
Pi is 3.14 with no units
2((225 / (0.08 x 3.14))^(1/2)) = 60 minutes.
0.08 x 3.14 = 0.251
225 / 0.251 = 896
square root of 896 = 29.9
2 x 29.9 = 60 minutes
Leak rate was 225 cubit feet in the first hour.
or, 7.48 us liquid gallons equals 1 cubic foot
Leak rate was 1,680 gallons in the first hour.
or $50 per barrel, and 42 gallons per barrel.
Leak rate is $2000 per hour! Plus cleanup!
Leak rate is growing exponentially over time. In other words, the leak rate will be $4000 more in the next hour! $16k in the next hour.
Fix your problems while they are small, before they turn into bigger problems!
[This message edited by still-living at 6:37 AM, October 5th (Friday)]
barcher144 ( member #54935) posted at 6:32 PM on Friday, October 5th, 2018
I'm an engineer...
The volume formula is:
V = 0.08 * pi * r * r
And the radius formula is:
r = 0.5 * t
So, plug the second equation into the first equation:
V = 0.08 * pi * (0.05 * t) * (0.05 * t)
Simplifying:
V = 0.0002 * pi * t * t
(practical interpretation: the volume increases as a function of time-squared, meaning that it accelerates over time... it's not linear).
Now, if V = 225, then you can solve for t:
225 = 0.0002 * pi * t * t
358098.9 = t * t
t = 598.4 minutes
Me: Crap, I'm 50 years old. D-Day: August 30, 2016. Two years of false reconciliation. Divorce final: Feb 1, 2021. Re-married: December 3, 2022.
ZenMumWalking ( member #25341) posted at 6:56 PM on Friday, October 5th, 2018
barcher put in .05 where it should have been .5, so numerically you have:
V = 0.08 * pi * (0.5 * t) * (0.5 * t)
=> V = 0.02 * pi * t * t
=> Now, if V = 225, then you can solve for t:
225 = 0.02 * pi * t * t
and approximating pi by 3.14, you get
t * t = 225/(0.02 * 3.14) = 3582.8
=> t = sqrt(3582.8) = approx 59.86 (up to round-off error)
or about 1 hour.
In general, the volume formula for a cylinder is pi*(r squared)*(height of the cylinder), so here the height is 0.08, which we are assuming is constant across time.
Me (BS), Him (WH): late-50's
3 DS: 26, 25, 22
M: 30+ (19 1/2 at Dday)
Dday: Dec 2008
Wanted R, not gonna happen (in permanent S)
Used to be DeadMumWalking, doing better now
PlanC ( member #47500) posted at 8:52 PM on Friday, October 5th, 2018
I’m not an engineer, but I like humorous science fiction, and accordingly was going to suggest that the answer is 42.
BS 50; xWW. 4 children.
DD 1: April 2013, confessed ONS June 2012
DD 2: March 2014, confessed affair August 2012 through March 2013
DD 3: October 2015, involuntarily confessed 5 additional ONS starting August 2014 through November 2014 (manic)
ZenMumWalking ( member #25341) posted at 9:52 PM on Friday, October 5th, 2018
I’m not an engineer
Nor do you play one on tv I assume.
but I like humorous science fiction, and accordingly was going to suggest that the answer is 42.
Me (BS), Him (WH): late-50's
3 DS: 26, 25, 22
M: 30+ (19 1/2 at Dday)
Dday: Dec 2008
Wanted R, not gonna happen (in permanent S)
Used to be DeadMumWalking, doing better now
Zigin ( new member #56420) posted at 2:54 AM on Saturday, October 6th, 2018
Translation: There are some seriously smart men and women on this board.
Me: BH, 40s
Her: WS, 40s
Two children, one at home, one in school.
barcher144 ( member #54935) posted at 3:05 AM on Saturday, October 6th, 2018
I'm an engineer...
Translation: I don't read very carefully.
Me: Crap, I'm 50 years old. D-Day: August 30, 2016. Two years of false reconciliation. Divorce final: Feb 1, 2021. Re-married: December 3, 2022.
Emotionalhell ( member #39902) posted at 3:10 AM on Saturday, October 6th, 2018
This thread made me smile:)
Me BS x2. 50ish Divorced WH #1. IHS with wayward #2 Dday #1 Oct. 2014Dday # 2 August 2018. Dday #3 December 17th.
BearlyBreathing ( member #55075) posted at 3:42 AM on Saturday, October 6th, 2018
42 is the answer... to everything
Me: BS 57 (49 on d-day)Him: *who cares ;-) *. D-Day 8/15/2016 LTA. Kinda liking my new life :-)
**horrible typist, lots of edits to correct. :-/ **
Greeneyesbluezy ( member #58158) posted at 4:37 AM on Saturday, October 6th, 2018
Can I say I hate you guys? Like totally hate you??
!
Jokes aside, best of luck!!!
Stop right there, I already don't give a fuck.
StillLivin (original poster member #40229) posted at 4:19 PM on Saturday, October 6th, 2018
Thank you everyone. Sorry I didn't come back to respond sooner. I did exactly what you said Barcher, but I was doubting myself. I got a 100 on the homework so I guess I'm not quite as dumb as I thought. Yikes I'm still in shock I got all the answers correct because i seriously don't know for certain when I've guessed right on the formulas.
You guys are hilarious!!!
"Bitch please a good man can't be stolen." ROFLMAO - SBB: 7/2/2014
still-living ( member #30434) posted at 4:25 PM on Saturday, October 6th, 2018
But what about significant digits?
WhatsRight ( member #35417) posted at 12:56 AM on Friday, October 12th, 2018
"Noone can make you feel inferior without your concent." Eleanor Roosevelt
I will not be vanquished. Rose Kennedy
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