The Student Room Group

Differential reservoir question

I hope I did the first part right but I don’t think I understand the second part at all.
(edited 2 years ago)
Reply 1
Original post by Eris13696
I hope I did the first part right but I don’t think I understand the second part at all.

Do you mean the added water part of the differential equation, which is an additive constant as the water is added at a constant rate?
If so, it should just be the added 90,000 l/min, where litres per min is converted to the height d per min.
(edited 2 years ago)
Reply 2
Original post by mqb2766
Do you mean the added water part of the differential equation, which is an additive constant as the water is added at a constant rate?
If so, it should just be the added 90,000 l/min, where litres per min is converted to the height d per

Oh wait I see, we just multiply the 1500x60 and the and then do d=v/a. This here, why is it -10^-5 didn’t we say k=5x10^-6
(edited 2 years ago)
Reply 3
Can you upload your working for the differential equation? For both the inflow and the outflow terms, you need to convert the given values to metres per minute, where the metres refers to the depth.
Reply 4
Original post by mqb2766
Can you upload your working for the differential equation? For both the inflow and the outflow terms, you need to convert the given values to metres per minute, where the metres refers to the depth.

Here’s my working so far.
Reply 5
You have the
+ 1.5 * 10^(-3)
correct and your first part agrees with the answer 1/2 way down the page (and I believe is correct), but they transcribe it incorrectly at the bottom. So your answer looks ok.

One problem though is that in your working you write
d = ...
when really it should be
d d/dt = ...
I guess you'd get marked down a bit for this as they mean different things.
(edited 2 years ago)
Reply 6
Original post by mqb2766
You have the
+ 1.5 * 10^(-3)
correct and your first part agrees with the answer 1/2 way down the page (and I believe is correct), but they transcribe it incorrectly at the bottom. So your answer looks ok.

One problem though is that in your working you write
d = ...
when really it should be
d d/dt = ...
I guess you'd get marked down a bit for this as they mean different things.

Thank you for the tip about dd/dt, will keep it in mind ;D

Quick Reply

Latest