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diff --git a/Engineering_Physics/Chapter_8.ipynb b/Engineering_Physics/Chapter_8.ipynb new file mode 100755 index 00000000..60f3ed3a --- /dev/null +++ b/Engineering_Physics/Chapter_8.ipynb @@ -0,0 +1,413 @@ +{ + "metadata": { + "name": "" + }, + "nbformat": 3, + "nbformat_minor": 0, + "worksheets": [ + { + "cells": [ + { + "cell_type": "heading", + "level": 1, + "metadata": {}, + "source": [ + "Chapter 8: Sound Waves and Acoustics of Buildings \n" + ] + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.1, Page 8.17" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Given \n", + "v = 34500 # speed of sound in cm/sec\n", + "f = 20 # lower limit of frequency for human hearing ear in Hz\n", + "f_ = 20000 # upper limit of frequency for human hearing ear in Hz\n", + "\n", + "#Clculations\n", + "l1 = v / f\n", + "l2 = v / f_\n", + "\n", + "#Results\n", + "print \"Wavelength range of the sound wave is %.f cm to %.f cm.\"%(l1,l2)" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Wavelength range of the sound wave is 1725 cm to 1 cm.\n" + ] + } + ], + "prompt_number": 2 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.2, Page 8.18" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from math import sqrt\n", + "\n", + "# Given \n", + "T = 373. # temperature in kelvin\n", + "d = 1.293e-3 # density of air at S.T.P. in gm/cm^3\n", + "d_ = 13.6 # density of mercury in gm/cm^3\n", + "Cp = 0.2417 # specific heat of air at constant pressure \n", + "Cv = 0.1715 # specific heat of air at constant volume\n", + "g = 980 # gravitational constant i dynes/cm^3\n", + "\n", + "#calculations\n", + "p = 76 * d_ * g\n", + "gama = Cp / Cv\n", + "v = sqrt(gama * (p / d))\n", + "v_ = v * sqrt(T / 273)\n", + "\n", + "#Result\n", + "print \"Velocity of sound in the air in %.f cm/sec.\"%v_\n", + "#Incorrect answer in textbook" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Velocity of sound in the air in 38839 cm/sec.\n" + ] + } + ], + "prompt_number": 3 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.3, Page 8.18" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from math import sqrt\n", + "\n", + " \n", + "# Given that\n", + "n = 512. # frequency of tuning fork in Hz \n", + "T = 290. # temperature in kelvin\n", + "l = 66.5 # wavelength of the gas emitted by tuning fork in cm\n", + "d = 1.293e-3 # density of air at S.T.P. in gm/cm^3\n", + "d_ = 13.6 # density of mercury in gm/cm^3\n", + "g = 980 # gravitational constant i dynes/cm^3\n", + "\n", + "#Calculations\n", + "p = 76 * d_ * g# calculation for pressure\n", + "v_ = n * l# calculation for velocity of sound in air at temperature 17 c \n", + "v = v_ * sqrt(273 / T)# calculation for velocity of sound in air at temp 0 c\n", + "gama = v**2 * (d / p)# calculation for ratio of two specific heat\n", + "\n", + "#Result\n", + "print \"Ratio of two principal specific heats of air is %.2f\"%gama" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Ratio of two principal specific heats of air is 1.39\n" + ] + } + ], + "prompt_number": 4 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.4, Page 8.19" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Given \n", + "A = 15 * 30 # area of the floor in square meter\n", + "h = 6 # height of hall in meter\n", + "N = 500 # no. of people\n", + "t = 1.36 # optimum time for orchestral music in sec\n", + "k = 0.44 # absorption coefficient per person\n", + "\n", + "#Calculations\n", + "aS = 0.161 * ((A * h) / t)\n", + "a = N * k\n", + "a_ = aS - a\n", + "w = a_ + (N / 2) * k + (N / 2) * 0.02\n", + "t = (0.161 * (A * h)) / w\n", + "\n", + "#Results\n", + "print \"Coefficient of absorption to be provided by the walls, floor and ceiling when the hall is fully occupied is %.f SI unit.\"%a_\n", + "print \"Reverberation time if only half upholstered seats are occupied is %.2f sec.\"%t\n", + "#Answer varies due to rounding-off " + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "319.632352941\n", + "Coefficient of absorption to be provided by the walls, floor and ceiling when the hall is fully occupied is 100 SI unit.\n", + "Reverberation time if only half upholstered seats are occupied is 2.03 sec.\n" + ] + } + ], + "prompt_number": 6 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.5, Page 8.19" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Given\n", + "V = 8000 # volume of hall in meter^3\n", + "t = 1.8 # reverberation time in sec\n", + "\n", + "#Calculation\n", + "aS = (0.161 * V) / t# calculation for the total absorption constant\n", + "\n", + "#Result\n", + "print \"The total absorption constant = %.3f O.W.U.\"%aS\n", + "#Incorrect answer in the textbook" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The total absorption constant = 715.556 O.W.U.\n" + ] + } + ], + "prompt_number": 10 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.6, Page 8.20" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Given \n", + "V = 1700 # volume in meter^3\n", + "a1 = 98 # area of plastered wall in m^2\n", + "a2 = 144 # area of plastered ceiling in m^2\n", + "a3 = 15 # area of wooden door in m^2\n", + "a4 = 88 # area of cushioned chairs in m^2\n", + "a5 = 150 # area of audience (each person) in m^2\n", + "k1 = 0.03 # coefficient of absorption for plastered wall in O.W.U.\n", + "k2 = 0.04 # coefficient of absorption for plastered ceiling in O.W.U.\n", + "k3 = 0.06 # coefficient of absorption for wooden door in O.W.U.\n", + "k4 = 1 # coefficient of absorption for cushioned chair in O.W.U.\n", + "k5 = 4.7 # coefficient of absorption for audience (each person) in O.W.U.\n", + "\n", + "#Calculations\n", + "A1 = a1 * k1# calculation for the absorption by the plaster wall\n", + "A2 = a2 * k2# calculation for the absorption by the plastered ceiling\n", + "A3 = a3 * k3# calculation for wooden door\n", + "A4 = a4 * k4# calculation for cushioned chairs \n", + "A = A1 + A2 + A3 + A4# calculation for total absorption\n", + "T = 0.161 * (V / A)# calculation for reverberation time\n", + "\n", + "#Result\n", + "print \"Reverberation time is %.2f sec\"%T" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Reverberation time is 2.80 sec\n" + ] + } + ], + "prompt_number": 11 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.7, Page 8.20" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Given \n", + "V = 1400 # volume of hall in meter^3\n", + "C = 110 # seating capacity of hall \n", + "a1 = 98 # area of plastered wall in m^2\n", + "a2 = 144 # area of plastered ceiling in m^2\n", + "a3 = 15 # area of wooden door in m^2\n", + "a4 = 88 # area of cushioned chairs in m^2\n", + "a5 = 150 # area of audience (each person) in m^2\n", + "k1 = 0.03 # coefficient of absorption for plastered wall in O.W.U.\n", + "k2 = 0.04 # coefficient of absorption for plastered ceiling in O.W.U.\n", + "k3 = 0.06 # coefficient of absorption for wooden door in O.W.U.\n", + "k4 = 1 # coefficient of absorption for cushioned chair in O.W.U.\n", + "k5 = 4.7 # coefficient of absorption for audience (each person) in O.W.U.\n", + "\n", + "#Calculations\n", + "A1 = a1 * k1# calculation for the absorption by the plaster wall\n", + "A2 = a2 * k2# calculation for the absorption by the plastered ceiling\n", + "A3 = a3 * k3# calculation for wooden door\n", + "A4 = a4 * k4# calculation for cushioned chairs \n", + "A5 = C*k5 # the absorption due to persons\n", + "A = A1 + A2 + A3 + A4 + A5 # calculation for total absorption\n", + "T = (0.161 * V) / A# calculation for the reverberation time\n", + "\n", + "#Result\n", + "print \"Reverberation time is %.3f sec\"%T" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Reverberation time is 0.367 sec\n" + ] + } + ], + "prompt_number": 12 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.8, Page 8.21" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Given \n", + "V = 980 # volume in meter^3\n", + "a1 = 150 # area of wall in m^2\n", + "a2 = 95 # area of ceiling in m^2\n", + "a3 = 90 # area of floor in m^2\n", + "k1 = 0.03 # coefficient of absorption for wall in O.W.U.\n", + "k2 = 0.80 # coefficient of absorption for ceiling in O.W.U.\n", + "k3 = 0.06 # coefficient of absorption for floor in O.W.U.\n", + "\n", + "#calculations\n", + "A1 = a1 * k1\n", + "A2 = a2 * k2\n", + "A3 = a3 * k3\n", + "A = A1 + A2 + A3\n", + "T = 0.161 * (V / A)\n", + "\n", + "#Result\n", + "print \"Reverberation time = %.2f sec\"%T" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Reverberation time = 1.84 sec\n" + ] + } + ], + "prompt_number": 13 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8.9, Page 8.21" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# Given \n", + "V = 980 # volume in meter^3\n", + "a = 1.58 # area of window in m^2\n", + "I_ = 1e-12 # standard intensity level of sound wave in W/m^2\n", + "l = 60 # intensity level in dB\n", + "\n", + "#calculations\n", + "I = I_ * 10**(l / 10)# calculation for intensity\n", + "AP = I * a# calculation for acoustic power\n", + "\n", + "#Result\n", + "print \"Acoustic power = %.2e watt\"%AP" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Acoustic power = 1.58e-06 watt\n" + ] + } + ], + "prompt_number": 14 + } + ], + "metadata": {} + } + ] +}
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