A tank initially contains 120 L of pure water. A mixture containing a concentrat

Nann

Nann

Answered question

2021-10-19

A tank initially contains 120 L of pure water. A mixture containing a concentration of γ g/L of salt enters the tank at a rate of 2 L/min, and the well-stirred mixture leaves the tank at the same rate. Find an expression in terms of γ for the amount of salt in the tank at any time t. Also find the limiting amount of salt in the tank as t

Answer & Explanation

diskusje5

diskusje5

Skilled2021-10-20Added 82 answers

Step 1
Let Q(t) salt content of tank at time t, be
the initial salt content is Q(0)=0
The differential equation that describes this issue is dQ dt =raterateout
rate∈=2γ
rateout=Q(t)1202
Consequently, the problem of beginning value is
dQ dt =2γQ60
Q(0)=0
Step 2
Division with differential equation Q120γ to obtain the standard separable equation.
This is acceptable for everyone. Q120
 dy  dx Q120γ=160
Integrate both parties in relation to t
Keeping in mind the chain rule, you should be aware that the integration of the left side may be expressed as simply "integration with respect to Q."
1Q120γdQ=(160) dt 
lnmidQ120γmid+C1=t60+C2
midQ120γmid=et60eC2C1
Since C1 and C2 are constants eC2C1 is a positive constant. Call it C
The right side of the equation is positive for all t, as you can see.
Notice that Q<120γ (because 120γ is max. amount of salt in the tank)
120γQ=Cet60
Q=120γCet60
Step 3
Calculate constant C using the starting conditions.
Q(0)=0
120γCe060=0
C=120γ
Consequently, the salt content Q(t) each moment t is in the tank
Q(t)=120γ120γet60
Additionally, the tank's maximum salt content is
limtQ(t)=limt(120γ120γet60)=120γ

Vasquez

Vasquez

Expert2023-05-14Added 669 answers

At time t=0, the tank contains 120 L of pure water, which means there is no salt in the tank initially. Therefore, S(0) = 0 g.
Now, let's consider the rate at which salt enters the tank. The mixture entering the tank has a concentration of γ g/L of salt, and the rate of flow is 2 L/min. This means that the amount of salt entering the tank per minute is *2γ g/min*.
Since the mixture entering the tank is well-stirred and leaves the tank at the same rate, the amount of salt leaving the tank per minute is also 2γg/min. Therefore, the rate of change of the amount of salt in the tank is given by:
dSdt=(rate of salt entering the tank)(rate of salt leaving the tank)
dSdt=2γ2γ=0
We obtained 0 as the derivative of S(t) with respect to t. This implies that the amount of salt in the tank is constant over time. Therefore, the expression for the amount of salt in the tank at any time t is:
S(t)=S(0)+0tdSdtdt
S(t)=0+0t0dt
S(t)=0
Hence, the amount of salt in the tank at any time t is 0 g.
Next, let's find the limiting amount of salt in the tank as t approaches infinity (t). In this case, we can evaluate the integral from 0 to infinity:
S()=S(0)+0dSdtdt
S()=0+00dt
S()=0
Therefore, the limiting amount of salt in the tank as t approaches infinity is 0 g.
RizerMix

RizerMix

Expert2023-05-14Added 656 answers

Answer:
- The expression for the amount of salt in the tank at any time t is S(t)=120γ+2γt.
- The limiting amount of salt in the tank as t is infinity.
Explanation:
Let t be the time in minutes.
Let V(t) be the volume of water in the tank at time t in liters.
Let S(t) be the amount of salt in the tank at time t in grams.
Given that the tank initially contains 120 L of pure water, we can express V(t) as follows:
V(t)=120+(2Lmin)·t
The concentration of salt in the mixture entering the tank is γ g/L. Since the mixture enters and leaves the tank at the same rate, the concentration of salt in the tank remains constant over time.
Therefore, the amount of salt in the tank at any time t is given by:
S(t)=γ·V(t)
Substituting the expression for V(t), we have:
S(t)=γ·(120+(2Lmin)·t)
Simplifying this expression, we get:
S(t)=120γ+2γt
Thus, the amount of salt in the tank at any time t is given by the expression 120γ+2γt.
Now, let's determine the limiting amount of salt in the tank as t. In the long run, the tank will continuously receive the mixture with concentration γ, while an equal volume of mixture leaves the tank. Therefore, the concentration of salt in the tank will stabilize at γ g/L.
As t approaches infinity, the amount of salt in the tank can be calculated as:
limtS(t)=limt(120γ+2γt)
Since the term 2γt becomes infinitely large as t approaches infinity, the limiting amount of salt in the tank as t is infinity.
karton

karton

Expert2023-05-14Added 613 answers

To solve the given problem, we'll first find an expression for the amount of salt in the tank at any time t, and then determine the limiting amount of salt as t approaches infinity.
Let's denote the amount of salt in the tank at time t as Q(t). Initially, the tank contains 120 L of pure water, so there is no salt present: Q(0)=0.
The rate at which the mixture enters the tank is 2 L/min, and the concentration of salt in the entering mixture is γ g/L. This means that the amount of salt entering the tank per minute is 2γ g/min.
The mixture is well-stirred, so the concentration of salt remains uniform throughout the tank. Since the mixture is leaving the tank at the same rate of 2 L/min, the amount of salt leaving the tank per minute is also 2γ g/min.
Therefore, the rate of change of the amount of salt in the tank can be expressed as:
dQdt={ratein}{rate out}=2γ2γ=0
This implies that the amount of salt in the tank remains constant over time, as there is no net change in the salt content.
Hence, the expression for the amount of salt in the tank at any time t is:
Q(t)=Q(0)=0
The limiting amount of salt in the tank as t can be found by taking the limit of Q(t) as t approaches infinity:
limtQ(t)=limt0=0
Therefore, the limiting amount of salt in the tank as t is 0 g.

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