{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 21: Kinematics of rigid body" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 21.11: Instantaneous_Centre_of_rotation_in_plane_motion.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Initilization of variables\n", "v_a=2 // m/s // velocity at end A\n", "r=0.05 // m // radius of the disc\n", "alpha=30 // degree // angle made by the bar with the horizontal\n", "// Calculations \n", "// Soving eqn's 1 & 2 and substuting eqn 1 in it we get eq'n for omega as,\n", "omega=(v_a*(sind(alpha))^2)/(r*cosd(alpha)) // radian/second\n", "// Results\n", "clc\n", "printf('The anguar veocity of the bar is %f radian/second \n',omega)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 21.12: Instantaneous_Centre_of_rotation_in_plane_motion.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Initilization of variables\n", "l=0.6 // m \n", "r=0.12 // m \n", "theta=30 // degree // angle made by OA with the horizontal\n", "phi=5.7 // degree // from EX 21.5\n", "N=300\n", "// Calculations\n", "// Let the angular velocity of the connecting rod be (omega_ab) which is given from eqn's 1 & 4 as,\n", "omega_oa=(2*%pi*N)/(60) // radian/ second\n", "// Now,in triangle IBO.\n", "IB=(l*cosd(phi)*tand(theta))+(r*sind(theta)) // m\n", "IA=(l*cosd(phi))/(cosd(theta)) // m\n", "// from eq'n 5\n", "v_b=(r*omega_oa*IB)/(IA) // m/s\n", "// From eq'n 6\n", "omega_ab=(r*omega_oa)/(IA) // radian/second\n", "// Results\n", "clc\n", "printf('The velocity at B is %f m/s \n',v_b)\n", "printf('The angular velocity of the connecting rod is %f radian/second \n',omega_ab)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 21.13: Instantaneous_Centre_of_rotation_in_plane_motion.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Initilization of variables\n", "omega_ab=5 // rad/s // angular veocity of the bar\n", "AB=0.20 // m\n", "BC=0.15 // m\n", "CD=0.3 // m\n", "theta=30 // degree // where theta= angle made by AB with the horizontal\n", "alpha=60 // degree // where alpha=angle made by CD with the horizontal\n", "// Calculations\n", "// Consider triangle BIC\n", "IB=sind(alpha)*BC*1 // m\n", "IC=sind(theta)*BC*1 // m\n", "v_b=omega_ab*AB // m/s\n", "// let the angular velocity of the bar BC be omega_bc\n", "omega_bc=v_b/IB // radian/second\n", "v_c=omega_bc*IC // m/s\n", "// let the angular velocity of bar DC be omega_dc\n", "omega_dc=v_c/CD // radian/second\n", "// Results\n", "clc\n", "printf('The angular velocity of bar BC is %f rad/s \n',omega_bc)\n", "printf('The angular velocity of bar CD is %f rad/s \n',omega_dc)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 21.1: Linear_and_angular_velocity_linear_and_angular_acceleration_in_rotation.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Initilization of variables\n", "N=1800 // r.p.m // Speed of the shaft\n", "t=5 // seconds // time taken to attain the rated speed // case (a)\n", "T=90 // seconds // time taken by the unit to come to rest // case (b)\n", "// Calculations\n", "omega=(2*%pi*N)/(60)\n", "// (a)\n", "// we take alpha_1,theta_1 & n_1 for case (a)\n", "alpha_1=omega/t // rad/s^2 //\n", "theta_1=(omega^2)/(2*alpha_1) // radian\n", "// Let n_1 be the number of revolutions turned,\n", "n_1=theta_1*(1/(2*%pi))\n", "// (b)\n", "// similarly we take alpha_1,theta_1 & n_1 for case (b)\n", "alpha_2=(omega/T) // rad/s^2 // However here alpha_2 is -ve\n", "theta_2=(omega^2)/(2*alpha_2) // radians\n", "// Let n_2 be the number of revolutions turned,\n", "n_2=theta_2*(1/(2*%pi))\n", "// Results\n", "clc\n", "printf('(a) The no of revolutions the unit turns to attain the rated speed is %f \n',n_1)\n", "printf('(b) The no of revolutions the unit turns to come to rest is %f \n',n_2)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 21.2: Absolute_and_relative_velocity_in_plane_motion.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Initilization of variables\n", "r=1 // m // radius of the cylinder\n", "v_c=20 // m/s // velocity of the cylinder at its centre\n", "// Calculations\n", "// The velocity of point E is given by using the triangle law as,\n", "v_e=sqrt(2)*v_c // m/s \n", "// Similarly the velocity at point F is given as,\n", "v_f=2*v_c // m/s \n", "// Results\n", "clc\n", "printf('The velocity of point E is %f m/s \n',v_e)\n", "printf('The velocity of point F is %f m/s \n',v_f)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 21.3: Absolute_and_relative_velocity_in_plane_motion.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Initilization of Variables\n", "v_1=3 // m/s // uniform speed of the belt at top\n", "v_2=2 // m/s // uniform speed of the belt at the bottom\n", "r=0.4 // m // radius of the roller\n", "// Calculations\n", "// equating eq'ns 2 & 4 and solving for v_c & theta' (angular velocity). We use matrix to solve the eqn's\n", "A=[1 r;1 -r]\n", "B=[v_1;v_2]\n", "C=inv(A)*B\n", "// Results\n", "clc\n", "printf('The linear velocity (v_c) at point C is %f m/s \n',C(1))\n", "printf('The angular velocity at point C is %f radian/seconds \n', C(2))\n", "// NOTE: The answer of angular velocity is incorrect in the book" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 21.4: Absolute_and_relative_velocity_in_plane_motion.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Initilization of Variables\n", "l=1 // m // length of bar AB\n", "v_a=5 // m/s // velocity of A\n", "theta=30 // degree // angle made by the bar with the horizontal\n", "// Calculations\n", "// From the vector diagram linear velocity of end B is given as,\n", "v_b=v_a/tand(theta) // m/s \n", "// Now let the relative velocity be v_ba which is given as,\n", "v_ba=v_a/sind(theta) // m/s\n", "// Now let the angular velocity of the bar be theta_a which is given as,\n", "theta_a=(v_ba)/l // radian/second\n", "// Velocity of point A\n", "v_a=(l/2)*theta_a // m/s\n", "// Magnitude of velocity at point C is,\n", "v_c=v_a // m/s // from the vector diagram\n", "// Results\n", "clc\n", "printf('(a) The angular velocity of the bar is %f radian/second \n',theta_a)\n", "printf('(b) The velocity of end B is %f m/s \n',v_b)\n", "printf('(c) The velocity of mid point C is %f m/s \n',v_c)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 21.5: Absolute_and_relative_velocity_in_plane_motion.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Initilization of Variables\n", "r=0.12 // m // length of the crank\n", "l=0.6 // m // length of the connecting rod\n", "N=300 // r.p.m // angular velocity of the crank\n", "theta=30 // degree // angle made by the crank with the horizontal\n", "// Calculations\n", "// Now let the angle between the connecting rod and the horizontal rod be phi\n", "phi=asind((r*sind(theta))/(l)) // degree\n", "// Now let the angular velocity of crank OA be omega_oa, which is given by eq'n\n", "omega_oa=(2*%pi*N)/(60) // radian/second\n", "// Linear velocity at A is given as,\n", "v_a=r*omega_oa // m/s\n", "// Now using the sine rule linear velocity at B can be given as,\n", "v_b=(v_a*sind(35.7))/(sind(84.3)) // m/s\n", "// Similarly the relative velocity (assume v_ba) is given as,\n", "v_ba=(v_a*sind(60))/(sind(84.3))\n", "// Angular velocity (omega_ab) is given as,\n", "omega_ab=v_ba/l // radian/second\n", "// Results\n", "clc\n", "printf('(a) The angular velocity of the connecting rod is %f radian/second \n',omega_ab)\n", "printf('(b) The velocity of the piston when the crank makes an angle of 30 degree is %f m/s \n',v_b)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 21.6: Instantaneous_Centre_of_rotation_in_plane_motion.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Initiization of variables\n", "r=1 // m // radius of the cylinder\n", "v_c=20 // m/s // velocity at the centre\n", "// Calculations\n", "// Angular velocity is given as,\n", "omega=v_c/r // radian/second\n", "// Velocity at point D is\n", "v_d=omega*sqrt(2)*r // m/s // from eq'n 1\n", "// Now, the velocity at point E is,\n", "v_e=omega*2*r // m/s \n", "// Results\n", "clc\n", "printf('The velocity at point D is %f m/s \n',v_d)\n", "printf('The velocity at point E is %f m/s \n',v_e)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 21.7: Instantaneous_Centre_of_rotation_in_plane_motion.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Initilization of Variables\n", "r=5 // cm // radius of the roller\n", "AB=0.1 // m\n", "v_a=3 // m/s // velocity at A\n", "v_b=2 // m/s // velocity at B\n", "// Calculations\n", "// Solving eqn's 1 & 2 using matrix for IA & IB we get,\n", "A=[-2 3;1 1]\n", "B=[0;AB]\n", "C=inv(A)*B\n", "d1=C(2)*10^2 // cm // assume d1 for case 1\n", "// Similary solving eqn's 3 & 4 again for IA & IB we get,\n", "P=[-v_b v_a;1 -1]\n", "Q=[0;AB]\n", "R=inv(P)*Q\n", "d2=R(2)*10^2 // cm // assume d2 for case 2\n", "// Results\n", "clc\n", "printf('The distance d when the bars move in the opposite directions are %f cm \n',d1)\n", "printf('The distance d when the bars move in the same directions are %f cm \n',d2)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 21.8: Instantaneous_Centre_of_rotation_in_plane_motion.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Initilization of Variables\n", "v_c=1 // m/s // velocity t the centre\n", "r1=0.1 // m \n", "r2=0.20 // m\n", "EB=0.1 // m\n", "EA=0.3 // m\n", "ED=sqrt(r1^2+r2^2) // m\n", "// Calculations\n", "// angular velocity is given as,\n", "omega=v_c/r1 // radian/seconds\n", "// Velocit at point B\n", "v_b=omega*EB // m/s \n", "// Velocity at point A\n", "v_a=omega*EA // m/s\n", "// Velocity at point D\n", "v_d=omega*ED // m/s\n", "// Results\n", "clc\n", "printf('The velocity at point A is %f m/s \n',v_a)\n", "printf('The velocity at point B is %f m/s \n',v_b)\n", "printf('The velocity at point D is %f m/s \n',v_d)" ] } , { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 21.9: Instantaneous_Centre_of_rotation_in_plane_motion.sce" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [ "// Initilization of variables\n", "l=1 // m // length of bar AB\n", "v_a=5 // m/s // velocity at A\n", "theta=30 // degree // angle made by the bar with the horizontal\n", "// Calculations\n", "IA=l*sind(theta) // m\n", "IB=l*cosd(theta) // m\n", "IC=0.5 // m // from triangle IAC\n", "// Angular veocity is given as,\n", "omega=v_a/(IA) // radian/second\n", "v_b=omega*IB // m/s\n", "v_c=omega*IC // m/s\n", "// Results\n", "clc\n", "printf('The velocity at point B is %f m/s \n',v_b)\n", "printf('The velocity at point C is %f m/s \n',v_c)" ] } ], "metadata": { "kernelspec": { "display_name": "Scilab", "language": "scilab", "name": "scilab" }, "language_info": { "file_extension": ".sce", "help_links": [ { "text": "MetaKernel Magics", "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md" } ], "mimetype": "text/x-octave", "name": "scilab", "version": "0.7.1" } }, "nbformat": 4, "nbformat_minor": 0 }