Chapter 4.2, Problem 9E

(Electrical eng.) The amplification of electronic circuits is measured in units of decibels, which is calculated as the following: 10LOG(Po/Pi) Po is the power of the output signal, and Pi is the power of the input signal. Using this formula, write, compile, and run a C++ program to calculate and display the decibel amplification, in which the output power is 50 times the input power. Verify your program’s result by doing a hand calculation. After verifying that your program is working correctly, use it to determine the amplification of a circuit, where output power is 4.639 watts and input power is 1 watt.

(General math) a. Design, write, compile, and run a C++ program to calculate the volume of a sphere with a radius, r, of 2 in. The volume is given by this formula: Volume=4r33 b. Manually check the values computed by your program. After verifying that your program is working correctly, modify it to determine the volume of a cube with a radius of 1.67 in.

(General math) a. Design, write, compile, and run a C++ program that calculates and displays the area of a triangle, such as the one in Figure 2.18, with a base of 1 in and a height of 1.5 in. The area is given by this formula: Area=12(base)(height) b. Manually check the values computed by your program. After verifying that your program is working correctly, modify it to determine the area of a two-dimensional triangle with a base of 3.5 in and a height of 1.45 in.

(General math) a. Write a C++ program to calculate and display the value of the slope of the line connecting two points with the coordinates (3,7) and (8,12). Use the fact that the slope between two points with the coordinates (x1,y1)and(x2,y2)is(y2y1)/(x2x1). b. How do you know the result your program produced is correct? c. After verifying the output your program produces, modify it to determine the slope of the line connecting the points (2,10) and (12,6). d. What do you think will happen if you use the points (2,3) and (2,4), which results in a division by zero? How do you think this situation can be handled? e. If your program doesn’t already do so, change its output to this: The value of the slope is xxx.xx The xxx.xx denotes placing the calculated value in a field wide enough for three places to the left of the decimal point and two places to the right of it.

(General math) The perimeter, approximate surface area, and approximate volume of an in-ground pool are given by the following formulas: perimeter=2( length+width)volume=lengthwidthaveragedepthundergroundsurfacearea=2( length+width)averagedepth+lengthwidth Using these formulas as a basis, write a C++ program that accepts the length, width, and average depth measurements, and then calculates the pool’s perimeter, volume, and underground surface area. In writing your program, make these two calculations immediately after entering the input data:lengthwidthandlength+width. The results of these two calculations should be used as needed in the assignment statements for determining the perimeter, volume, and underground surface area without recalculating them for each equation. Verify your program’s results by doing a hand calculation, using the following test data :length=25feet,width=15feet,andaveragedepth=5.5feet. After verifying that your program is working, use it to complete the following chart:

(Electrical eng.) For the series circuit shown in Figure 3.16, the voltage drop, V2 , across resistor R2 and the power, P2 , delivered to this resistor are given by the formulas V2=IR2andP2=IV2,whereI=E/(R1+R2). Using these formulas, write, compile, and run a C++ program that prompts users for values of E, R1, and R2 ; calculates the voltage drop and power delivered to R2 ; and displays the results. Check your program by using the test data E=10volts,R1=100ohms,andR2=200ohms. After finishing your verification, use your program to complete the following chart:

(Electrical eng.) a. The voltage gain of an amplifier is given by this formula: voltagegain=[275 23 2 +0.5 f 2 ]n f is the frequency in Hz. n is the number of stages in the amplifier. Using this formula, write, compile, and run a C++ program to determine the value of the voltage gain for a four-stage amplifier operating at a frequency of 120 Hz. Your program should produce the following display: At a frequency of xxxxx hertz, the voltage gain is yyyyy Your program should replace xxxxx with the frequency and yyyyy with the voltage gain. b. Manually check the value your program produces. After verifying that your program is working correctly, modify it to determine the voltage gain of a 12-stage amplifier operating at a frequency of 9500 Hz.

(Hydraulics) a. Design, write, compile, and run a C++ program that calculates and displays the velocity of water flowing out of the tube shown in Figure 2.19. The velocity of water flowing into the tube is 1 ft/sec, the input tube radius is 0.75 in, and the output tube radius is 0.5 in. The output velocity is given by this formula: vout=vin( r in r out )2 v outistheoutputvelocity.v inistheinputvelocity.routistheradiusoftheoutputtube.r inistheradiusoftheinputtube. b. Manually check the values computed by your program. After verifying that your program is working correctly, modify it to determine the output velocity for a tube having an input radius of 1 in and an output radius of .75 in, when water is flowing into the tube at a rate of 1.5 ft/sec.

(Electrical eng.) a. Write, compile, and run a C++ program that calculates and displays the value of the current flowing through an RC circuit (see Figure 3.19). The circuit consists of a battery connected in a series to a switch, a resistor, and a capacitor. When the switch is closed, the current, i, flowing through the circuit is given by this formula: i=(EIR)et/RC Eisthevoltageofthebatteryinvolts.Risthevalueoftheresistorinohms.Cisthevalueofthecapacitorinfarads.tisthetimeinsecondsaftertheswitchisclosed.eisEulersnumber,whichis2.71828( roundedtofivedecimalplaces). Using this formula, write, compile, and run a C++ program to determine the voltage across the capacitor shown in Figure 3.19 when t is 0.31 seconds. (Note: The value of RC is referred to as the system’s time constant.) The program should prompt the user to enter appropriate values and use input statements to accept the data. In constructing the prompts, use statements such as “Enter the voltage of the battery.” Verify your program’s operation by calculating by hand the current for the following test data: Testdataset1:Voltage=20volts,R=10ohms,RC=0.044,t=0.023secondsTestdataset2:Voltage=35volts,R=10ohms,RC=0.16,t=0.067seconds b. Check the value computed by your program by hand. After verifying that your program is working correctly, use it to complete the following chart: