Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
unkabogable
Group Title
A trough filled w/ water's 2m long & has a cross section in the form of an isosceles trapezoid 30 cm wide at the bottom, 60 cm at the top & a height of 50 cm. If the trough leaks water at the rate of 2000 cm^3 / min, how fast is the water level falling when the water is 20 cm. deep.?
 2 years ago
 2 years ago
unkabogable Group Title
A trough filled w/ water's 2m long & has a cross section in the form of an isosceles trapezoid 30 cm wide at the bottom, 60 cm at the top & a height of 50 cm. If the trough leaks water at the rate of 2000 cm^3 / min, how fast is the water level falling when the water is 20 cm. deep.?
 2 years ago
 2 years ago

This Question is Closed

unkabogable Group TitleBest ResponseYou've already chosen the best response.0
@mukushla
 2 years ago

datanewb Group TitleBest ResponseYou've already chosen the best response.0
Hey there, not sure how far along you are in solving this problem, but the first step is to get an equation which relates the volume to the height. Once you have done that, rates of change usually involve differentiation. Since there are two rates of change, for volume and height, this problem lends itself well to implicit differentiation. Here is a very good video on implicit differentiation: http://ocw.mit.edu/courses/mathematics/1801singlevariablecalculusfall2006/videolectures/lecture5implicitdifferentiation/
 2 years ago

datanewb Group TitleBest ResponseYou've already chosen the best response.0
I figured enough time had passed, so here is the answer I got with the full work. Could someone check it? I'm learning this too, and not 100% confident. Thanks.
 2 years ago

unkabogable Group TitleBest ResponseYou've already chosen the best response.0
@datanewb the link you've given is not found..:(
 2 years ago

datanewb Group TitleBest ResponseYou've already chosen the best response.0
I'm sorry the link is not working for you. I tested it in IE and Chrome and it is working on my computer. As an alternative to the above link, you can go to http://ocw.mit.edu and navigate to mathematics > 18.01 > lectures > lecture 5. Or, simply do a Google search for "18.01 lec 5". The lecture video is the first result returned by Google. It's a 45 minute lecture, and the explanation builds off of the chain rule, so you should be familiar with that before watching the video. (The chain rule is explained in lecture 4).
 2 years ago

unkabogable Group TitleBest ResponseYou've already chosen the best response.0
@datanewb someone like you here at openstudy...gave me that answer too....however, he told me that the given V' is negative 2000 cm^3/min. for the problem stated above that its leaking a volume of 2000 right? so his answer is 5/2 cm/min.. which is which?? thank you!!
 2 years ago

datanewb Group TitleBest ResponseYou've already chosen the best response.0
Well, yes, it would be negative. Generally speaking you can set the isosceles trapezoid in any reference frame, and thus the answer could be negative or positive depending on how you framed the answer. The only thing that is imperative is that you be consistent. That said, as I drew the figure and framed my answer, the correct answer is certainly negative. 5/21 cm/s! Thank you for pointing out my error!
 2 years ago

amistre64 Group TitleBest ResponseYou've already chosen the best response.0
the negative in this case represents a direction as opposed to a decrease of speed. thats understood right?
 2 years ago

unkabogable Group TitleBest ResponseYou've already chosen the best response.0
yes...thank you!!
 2 years ago
See more questions >>>
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.