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3 years ago

Define the hydraulic diameter for a rectangular duct

Engineering

1 answer:

8090 [49]3 years ago

4 0

Answer with Explanation:

Hydraulic diameter is a term analogous to the diameter of the circular sectional pipe but used for the cases when the cross sectional shape of the pipe is non circular.

It serves as an equivalent diameter that is used to calculate the Reynolds number for the flow.

The hydraulic diameter is 4 times the hydraulic radius of any section.

For a rectangular duct as shown in the attached figure

$R_{h}=\frac{Wetted_{Area}}{Wetted_{perimeter}}\\\\R_h=\frac{d\times b}{2(d+b)}\\\\\therefore D_{h}=4\times R_{h}=4\times \frac{db}{2(d+b)}=\frac{2db}{(d+b)}$

Where

$D_{h}$ is the hydraulic diameter of the duct with depth 'd' and width 'b'

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java Write a program that simulates tossing a coin. Prompt the user for how many times to toss the coin. Code a method with no p

max2010maxim [7]

Answer:

The solution code is written in Java.

public class Main {
public static void main(String[] args) {
Scanner inNum = new Scanner(System.in);
System.out.print("Enter number of toss: ");
int num = inNum.nextInt();
for(int i=0; i < num; i++){
System.out.println(toss());
}
}
public static String toss(){
String option[] = {"heads", "tails"};
Random rand = new Random();
return option[rand.nextInt(2)];
}
}

Explanation:

Firstly, we create a function toss() with no parameter but will return a string (Line 14). Within the function body, create an option array with two elements, "heads" and "tails" (Line 15). Next create a Random object (Line 16) and use nextInt() method to get random value either 0 or 1. Please note we need to pass the value of 2 into nextInx() method to ensure the random value generated is either 0 or 1. We use this generate random value as an index of option array and return either "heads" or "tails" as output (Line 17).

In the main program, we create Scanner object and use it to prompt user to input an number for how many times to toss the coin (Line 6 - 7). Next, we use the input num to control how many times a for loop should run (Line 9). In each round of the loop, call the function toss() and print the output to terminal (Line 10).

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3 years ago

Read 2 more answers

The entire system of components that produces power and transmits it to the road is called the vehicle's _____.

IrinaK [193]

Answer:

Powertrain

Explanation:

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3 years ago

What is the best countermeasure against social engineering?

Mkey [24]

Answer:

Hello Monk7294!

Answer:

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Explanation:

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2 years ago

Which bulb has the lowest total cost of operation? (a) Incandescent (b) Fluorescent (c) LED

Finger [1]

Answer: LED have the lowest cost of operation.

Explanation:

If we ignore the initial procurement cost of the items the operational cost of any device consuming electricity is given by

$Cost=Energy\times cost/unit$

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3 years ago

A parallel plates capacitor is filled with a dielectric of relative permittivity ε = 12 and a conductivity σ = 10^-10 S/m. The c

monitta

Answer:

t = 1.06 sec

Explanation:

Once disconnected from the battery, the capacitor discharges through the internal resistance of the dielectric, which can be expressed as follows:

R = (1/σ)*d/A, where d is is the separation between plates, and A is the area of one of the plates.

The capacitance C , for a parallel plates capacitor filled with a dielectric of a relative permittivity ε, can be expressed in this way:

C = ε₀*ε*A/d = 8.85*10⁻¹² *12*A/d

The voltage in the capacitor (which is proportional to the residual charge as it discharges through the resistance of the dielectric) follows an exponential decay, as follows:

V = V₀*e(-t/RC)

The product RC (which is called the time constant of the circuit) can be calculated as follows:

R*C = (1/10⁻¹⁰)*d/A*8.85*10⁻¹² *12*A/d

Simplifying common terms, we finally have:

R*C = 8.85*10⁻¹² *12 / (1/10⁻¹⁰) sec = 1.06 sec

If we want to know the time at which the voltage will decay to 3.67 V, we can write the following expression:

V= V₀*e(-t/RC) ⇒ e(-t/RC) = 3.67/10 ⇒ -t/RC = ln(3.67/10)= -1

⇒ t = RC = 1.06 sec.

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3 years ago