{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 22 Kinetics of Rigid Body Force and Acceleration" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 22.1 Relation between the translatory motion and rotary motion of a body in plane motion" ] }, { "cell_type": "code", "execution_count": 3, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "(a) The no of revolutions executed by the disc before coming to rest is 1500\n", "(b) The frictional torque is -5.003811 N-m\n" ] } ], "source": [ "import math\n", "#Initialization of variables\n", "N=1500 # r.p.m\n", "r=0.5 # m , radius of the disc\n", "m=300 # N , weight of the disc\n", "t=120 #seconds , time in which the disc comes to rest\n", "omega=0 \n", "g=9.81 #m/s**2\n", "#Calculations\n", "omega_0=(2*math.pi*N)/60 #rad/s\n", "#angular deceleration is given as,\n", "alpha=-(omega_0/t) #radian/second**2\n", "theta=(omega_0**2)/(2*(-alpha)) #radian\n", "#Let n be the no of revolutions taken by the disc before it comes to rest, then\n", "n=theta/(2*math.pi)\n", "#Now,\n", "I_G=((1/2)*m*r**2)/g\n", "#The frictional torque is given as,\n", "M=I_G*alpha #N-m\n", "#Results\n", "print('(a) The no of revolutions executed by the disc before coming to rest is %d'%n)\n", "print('(b) The frictional torque is %f N-m'%M)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 22.2 Relation between the translatory motion and rotary motion of a body in plane motion" ] }, { "cell_type": "code", "execution_count": 5, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "(a) The acceleration at the centre is 4.896389 m/s**2\n", "(b) The maximum angle of the inclined plane is 29.941943 degree\n" ] } ], "source": [ "# Initilization of variables\n", "s=1 # m\n", "mu=0.192 # coefficient of static friction\n", "g=9.81 # m/s**2\n", "# Calculations\n", "# The maximum angle of the inclined plane is given as,\n", "theta=math.degrees(math.atan(3*mu)) # degree\n", "a=(2/3)*g*math.sin(theta*180/math.pi) # m/s**2 # by solving eq'n 4\n", "v=math.sqrt(2*a*s) # m/s\n", "# Let the acceleration at the centre be A which is given as,\n", "A=g*math.sin(theta*math.pi/180) # m/s**2 # from eq'n 1\n", "# Results\n", "print('(a) The acceleration at the centre is %f m/s**2'%A)\n", "print('(b) The maximum angle of the inclined plane is %f degree'%theta)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 22.5 Relation between the translatory motion and rotary motion of a body in plane motion" ] }, { "cell_type": "code", "execution_count": 6, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "The acceleration of weight A is 1.081102 m/s**2\n" ] } ], "source": [ "# Initilization of variables\n", "W_a=25 # N \n", "W_b=25 # N \n", "W=200 # N # weight of the pulley\n", "i_g=0.2 # m # radius of gyration\n", "g=9.81 # m/s^2\n", "# Calculations\n", "# Solving eqn's 1 & 2 for acceleration of weight A (assume a)\n", "a=(0.15*W_a*g)/(((W*i_g**2)/(0.45))+(0.45*W_a)+((0.6*W_b)/(3))) # m/s^2\n", "# Results\n", "print('The acceleration of weight A is %f m/s**2'%a)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 22.8 Relation between the translatory motion and rotary motion of a body in plane motion" ] }, { "cell_type": "code", "execution_count": 8, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "The acceleration of the pool is 1.615819 m/s**2\n" ] } ], "source": [ "# Initilization of variables\n", "r_1=0.075 # m\n", "r_2=0.15 # m\n", "P=50 # N\n", "W=100 # N\n", "i_g=0.05 # m\n", "theta=30 # degree\n", "g=9.81 # m/s^2\n", "# Calculations\n", "# The eq'n for acceleration of the pool is given by solving eqn's 1,2 &3 as,\n", "a=(50*g*(r_2*math.cos(theta*math.pi/180)-r_1))/(100*((i_g**2/r_2)+r_2)) # m/s**2\n", "# Results\n", "print('The acceleration of the pool is %f m/s**2'%a)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 22.10 Relation between the translatory motion and rotary motion of a body in plane motion" ] }, { "cell_type": "code", "execution_count": 10, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "(a) The angular velocity of the rod is 4.101219 rad/sec\n", "(b) The reaction at the hinge is 103.227964 N\n" ] } ], "source": [ "# Initilization of variables\n", "L=1 # m # length of rod AB\n", "m=10 # kg # mass of the rod\n", "g=9.81 \n", "theta=30 # degree\n", "# Calculations\n", "# solving eq'n 4 for omega we get,\n", "omega=math.sqrt(2*16.82*math.sin(theta*math.pi/180)) # rad/s\n", "# Now solving eq'ns 1 &3 for alpha we get,\n", "alpha=(12/7)*g*math.cos(theta*math.pi/180) # rad/s\n", "# Components of reaction are given as,\n", "R_t=((m*g*math.cos(theta*math.pi/180))-((m*alpha*L)/4)) # N\n", "R_n=((m*omega**2*L)/(4))+(m*g*math.sin(theta*math.pi/180)) # N\n", "R=math.sqrt(R_t**2+R_n**2) # N \n", "# Results\n", "print('(a) The angular velocity of the rod is %f rad/sec'%omega)\n", "print('(b) The reaction at the hinge is %f N'%R)" ] } ], "metadata": { "kernelspec": { "display_name": "Python 3", "language": "python", "name": "python3" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 3 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython3", "version": "3.5.1" }, "widgets": { "state": {}, "version": "1.1.2" } }, "nbformat": 4, "nbformat_minor": 0 }