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3 years ago

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Answer all questions: 1) The electric field of an electromagnetic wave propagating in air is given by E(z,t) = 4cos(6 x 10^8 t -

2z) +3 sin(6 x 10 t -2z) (V/m). Find the associated magnetic field H(z,t)

1 answer:

Andre45 [30]3 years ago

4 0

Answer:

8

Step-by-step explanation:

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A 500-gallon tank initially contains 220 gallons of pure distilled water. Brine containing 5 pounds of salt per gallon flows int

Wittaler [7]

Answer: The amount of salt in the tank after 8 minutes is 36.52 pounds.

Step-by-step explanation:

Salt in the tank is modelled by the Principle of Mass Conservation, which states:

(Salt mass rate per unit time to the tank) - (Salt mass per unit time from the tank) = (Salt accumulation rate of the tank)

Flow is measured as the product of salt concentration and flow. A well stirred mixture means that salt concentrations within tank and in the output mass flow are the same. Inflow salt concentration remains constant. Hence:

$c_{0} \cdot f_{in} - c(t) \cdot f_{out} = \frac{d(V_{tank}(t) \cdot c(t))}{dt}$

By expanding the previous equation:

$c_{0} \cdot f_{in} - c(t) \cdot f_{out} = V_{tank}(t) \cdot \frac{dc(t)}{dt} + \frac{dV_{tank}(t)}{dt} \cdot c(t)$

The tank capacity and capacity rate of change given in gallons and gallons per minute are, respectivelly:

$V_{tank} = 220\\\frac{dV_{tank}(t)}{dt} = 0$

Since there is no accumulation within the tank, expression is simplified to this:

$c_{0} \cdot f_{in} - c(t) \cdot f_{out} = V_{tank}(t) \cdot \frac{dc(t)}{dt}$

By rearranging the expression, it is noticed the presence of a First-Order Non-Homogeneous Linear Ordinary Differential Equation:

$V_{tank} \cdot \frac{dc(t)}{dt} + f_{out} \cdot c(t) = c_0 \cdot f_{in}$ , where $c(0) = 0 \frac{pounds}{gallon}$ .

$\frac{dc(t)}{dt} + \frac{f_{out}}{V_{tank}} \cdot c(t) = \frac{c_0}{V_{tank}} \cdot f_{in}$

The solution of this equation is:

$c(t) = \frac{c_{0}}{f_{out}} \cdot ({1-e^{-\frac{f_{out}}{V_{tank}}\cdot t }})$

The salt concentration after 8 minutes is:

$c(8) = 0.166 \frac{pounds}{gallon}$

The instantaneous amount of salt in the tank is:

$m_{salt} = (0.166 \frac{pounds}{gallon}) \cdot (220 gallons)\\m_{salt} = 36.52 pounds$

3 0

3 years ago

Please help me on these questions and explain it thanks

BlackZzzverrR [31]

For problem 2:

The answer would be B) Car A travels more miles per gallon of fuel than Car B.

This is because Car B is shown on the graph to travel the same number of miles as Car A using 16 gallons of fuel, while Car A uses only 4 gallons. Thus, Car A travels further with less fuel.

For problem 3:

Let's write out the equation and try to solve.
5x + 1 = 3x + 7

First, subtract 3x from both sides.
5x - 3x + 1 = 3x - 3x + 7
2x + 1 = 7
Now, subtract one from both sides.

2x + 1 - 1 = 7 - 1
2x = 6

Finally, divide both sides by 2.
2x/2 = 6/2

x = 3

You should only get B) One solution

Hope that helped!

8 0

4 years ago

Convert an annual rate of 0.224% to a generation rate (20 years)

Sedaia [141]

2.78 that will be the awnser if you go gor it

4 0

3 years ago

What type of triangle is this?

Dominik [7]

Answer:

rectagular

Step-by-step explanation:

7 0

3 years ago

What are the steps to solving this limit?

patriot [66]

Answer:

lim(x---->0) = -5

Step-by-step explanation:

first: sin(x-π/2)= -cosx

so the equation will be :

lim(x---->0) = [-6cos(ax)-1}/cosx

solve :

lim(x---->0) = [-(6cos(a(0))-1}/cos(0)

cos0=1

lim(x---->0)=(-(6(1)-1)/1

lim(x---->0)=-6+1/1

lim(x---->0)=-5

6 0

3 years ago

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