{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 3: Velocity and Acceleration" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 3, Page 90" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable declaration\n", "OC=6.#in\n", "CP=24#in\n", "N=240#rpm\n", "X=45#degrees\n", "XP=19#in\n", "XC=6#in\n", "YP=32#in\n", "YC=9#in\n", "#Scalling off lenghts from fig , we have\n", "CI=2.77#in\n", "PI=2.33#in\n", "XI=2.33#in\n", "YI=3.48#in\n", "\n", "#Calculations\n", "Vc=((math.pi*N)/30)*(OC/12)#changing OP into feets\n", "print \"\\nw=%.2f ft/s\"%Vc\n", "#w=Vc/CI=Vp/PI=Vx/XI=Vy/YI\n", "w=Vc/CI\n", "Vp=w*PI\n", "Vx=w*XI\n", "Vy=w*YI\n", "\n", "#Results\n", "print \"velocity of points P, X and Y are %.2f ft/s, %.2f ft/s and %.1f ft/s respectively\"%(Vp,Vx,Vy)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "\n", "w=12.57 ft/s\n", "velocity of points P, X and Y are 10.57 ft/s, 10.57 ft/s and 15.8 ft/s respectively\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 4, Page 93" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable declaration\n", "OC=9.#inches\n", "CP=36.#inches\n", "XC=12#inches\n", "X=40#degrees\n", "CM=6.98#from the scaled figure\n", "N1=240#rpm\n", "N2=240#rpm (instantaneous) with angular aceleration (ao) 100 rad/s^2\n", "ao=100 #rad/s^2\n", "\n", "#Calculations&Results\n", "w=(math.pi*N1/30)\n", "a=w**2*(OC/12)\n", "print \"Centripetal acceleration = %.f ft/s^2\"%a\n", "Wr=w*CM/CP#rad/s^2\n", "f1=Wr**2*(CP/12)#centripetal component of acceleration of p realtive to C\n", "#Solution a)\n", "#given from fig 58(a)\n", "tp=296 \n", "cp=306\n", "ox=422\n", "f2=tp #Tangential component of acceleration of p realtive to C\n", "f3=cp#acceleration of p realtive to C\n", "fx=ox#acce;eration of x\n", "ar=f2/(CP/12)#angular acceleration of rod\n", "print \"\\nCase a) \\nap= %.f ft/s^2,\\nax= %.f ft/s^2 and\\nar= %.1f rad/s^2\"%(f3,fx,ar)\n", "\n", "#Solution b)\n", "#given from fig 58(b)\n", "oc1=474\n", "oc=480\n", "pt=238.\n", "pc=246\n", "xo=452\n", "f4=pt#Tangential component of acceleration of p realtive to C\n", "f5=pc#acceleration of p realtive to C\n", "Ar=f4/(CP/12)#angular acceleration of rod\n", "f6=ao*(OC/12)#tangential component of acceleration realtive to C\n", "Fx=xo#acce;eration of x\n", "print \"\\nCase b) \\nap= %.f ft/s^2,\\nax= %.f ft/s^2 and\\nar= %.1f rad/s^2\"%(f4,Fx,Ar)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Centripetal acceleration = 474 ft/s^2\n", "\n", "Case a) \n", "ap= 306 ft/s^2,\n", "ax= 422 ft/s^2 and\n", "ar= 98.7 rad/s^2\n", "\n", "Case b) \n", "ap= 238 ft/s^2,\n", "ax= 452 ft/s^2 and\n", "ar= 79.3 rad/s^2\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 5, Page 98" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable declaration\n", "AB=2.5#inches\n", "BC=7.#inches\n", "CD=4.5#inches\n", "DA=8#inches\n", "N=100#rpm\n", "X=60#degrees\n", "\n", "#Calculations\n", "w=(math.pi*N)/30\n", "#From triangle ABM we have \n", "AM=0.14#feet\n", "BM=0.12#feet\n", "Vb=w*AB/12#ft/s\n", "Vc=w*AM#ft/s\n", "Vcb=w*BM#ft/s\n", "fb=w**2*(AB/12)#ft/s^2\n", "bt=Vcb**2/(BC/12)#ft/s^2\n", "os=Vc**2/(CD/12)#ft/s^2\n", "#By measurement from acceleration diagram\n", "sc=19.1#ft/s^2\n", "tq=14.4#ft/s^2\n", "Acd=sc/(CD/12)\n", "Abc=tq/(BC/12)\n", "\n", "#Results\n", "print \"Vb=%.2f ft/s \\nVc=%.2f ft/s\\nVcb=%.2f ft/s\\nfb=%.2f ft/s^2\\nbt=%.2f ft/s^2\\nos=%.2f ft/s^2\"%(Vb,Vc,Vcb,fb,bt,os)\n", "print \"Angular acceleration of CD(counter-clockwise)= %.1f rad/s^2\"%Acd\n", "print \"Angular acceleration of BC(counter-clockwise)= %.1f rad/s^2\"%Abc" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Vb=2.18 ft/s \n", "Vc=1.47 ft/s\n", "Vcb=1.26 ft/s\n", "fb=22.85 ft/s^2\n", "bt=2.71 ft/s^2\n", "os=5.73 ft/s^2\n", "Angular acceleration of CD(counter-clockwise)= 50.9 rad/s^2\n", "Angular acceleration of BC(counter-clockwise)= 24.7 rad/s^2\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6, Page 106" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "OP=2#ft\n", "f=4#ft/s^2\n", "w=2 #rad/s (anticlockwise)\n", "a=5 #rad/s^2 (anticlockwise)\n", "Vpq=3 #ft/s\n", "\n", "#Calculations\n", "r=OP\n", "os=w**2*r#component 1\n", "sq=a*r#component 2\n", "qt=f#component 3\n", "tp=2*w*Vpq#component 4\n", "Aqo=(os**2+sq**2)**1./2#vector addition of component(a,b)\n", "Apq=(qt**2+tp**2)**1./2#vector addition of component(c,d)\n", "#Apo=Apq+Aqo (vector addition)\n", "Apo=((os-qt)**2+(sq+tp)**2)**(1./2)\n", "\n", "#Result\n", "print \"Acceleration of P realative to fixed point O is %.1f ft/s^2\"%Apo" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Acceleration of P realative to fixed point O is 22.4 ft/s^2\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 7, Page 110" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable declaration\n", "OC=8#inches\n", "CP=4#inches\n", "N=60#inches\n", "ON=15#inches\n", "RN=6.#inches\n", "X=120#degrees\n", "OP=10.6\n", "OQ=OP\n", "\n", "#Calculations\n", "#from fig 65(a)\n", "Vq=1.56#ft/s\n", "Vrn=0.74#ft/s\n", "#from fig 65(b)\n", "ftq=3.74#ft/s^2\n", "ftrn=2.03#ft/s^2\n", "w1=(math.pi*N)/30\n", "w=Vq/(OQ/12)\n", "wrn=Vrn/(RN/12)\n", "a=ftq/(OP/12)#Angular acceleration of ON\n", "a1=ftrn/(RN/12)#angular acceleration of RN\n", "\n", "#Results\n", "print \"W=%.2f rad/s\\nWrn=%.2f rad/s\"%(w,wrn)\n", "print \"Angular acceleration of ON= %.2f rad/s^2\\nAngular acceleration of RN=%.2f rad/s^2\"%(a,a1)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "W=1.77 rad/s\n", "Wrn=1.48 rad/s\n", "Angular acceleration of ON= 4.23 rad/s^2\n", "Angular acceleration of RN=4.06 rad/s^2\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 8, Page 112" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "\n", "#Variable declaration\n", "OC=3#inches\n", "CP=9.#inches\n", "N=1200 #rpm (clockwise)\n", "X=55 #degrees\n", "#from the figure 66\n", "OP=10.35#inches\n", "PM=10.74#inches\n", "OM=2.95#inches\n", "PC=12.84#inches\n", "PR=PC\n", "RV=2.49#inches\n", "UV=1.29#inches\n", "OU=5.90#inches\n", "PV=13.05#inches\n", "OV=6.06#inches\n", "OQ=OP\n", "\n", "#Calculations\n", "w=(math.pi*N)/30#the angular velocity of the cylinder line OP\n", "Vq=w*(OP/12)#the velocity of Q\n", "Vp=w*(PM/12)#The velocity of P\n", "w1=Vp/(CP/12)#The angular velocity of CP\n", "Vpq=w*(OM/12)#the velocity of sliding of the piston along the cylinder\n", "fq=w**2*(OQ/12)#the centripetal acceleration of Q\n", "Acp=w1**2*(PC/12)#The centripetal component of acceleration of P\n", "Atp=w**2*(RV/12)#The tangential component of acceleration of P\n", "acp=Atp/(CP/12)# The angular acceleration of the connecting rod CP\n", "f=w**2*(UV/12)#component c\n", "d=2*w*Vpq#component d\n", "Ap=w**2*PV#the resultant acceleration of P\n", "Apq=w**2*OV#the acceleration of P realative to Q\n", "\n", "#Results\n", "print \"The velocity and acceleration of the piston along the cylinder are %.1f ft/s and %.f ft/s^2 respectively\"\\\n", " \"\\nThe angular velocity and angular acceleration of the connecting rod cp are %.1f rad/s and %.f rad/s^2 respectively\"\\\n", " \"\\nAnd the coriolis component of the acceleration of P is %.f ft/s^2\"%(Vpq,f,w1,acp,d)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The velocity and acceleration of the piston along the cylinder are 30.9 ft/s and 1698 ft/s^2 respectively\n", "The angular velocity and angular acceleration of the connecting rod cp are 150.0 rad/s and 4369 rad/s^2 respectively\n", "And the coriolis component of the acceleration of P is 7764 ft/s^2\n" ] } ], "prompt_number": 9 } ], "metadata": {} } ] }