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{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter 08: Rotational work energy and momentum"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex8.1:pg-240"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": false
},
"outputs": [],
"source": [
" #Example 8_1\n",
" \n",
" \n",
" #To find the rotational kinetic energy\n",
"m=5.98*10**24 #units in Kg\n",
"r=6.37*10**6 #units in meters\n",
"I=(2/5)*m*r**2 #units in Kg meter**2\n",
"t=86400 #units in sec\n",
"w=(2*math.pi)/(t) #units in rad/sec\n",
"KE=0.5*(I*w**2) #units in joules\n",
"print \"The rotational kinetic energy is KE=\")\n",
"print KE)\n",
"print \"Joules\")\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex8.2:pg-242"
]
},
{
"cell_type": "code",
"execution_count": 9,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Angular acceleration is alpha= 0.384 rad/sec**2\n"
]
}
],
"source": [
" #Example 8_2\n",
" \n",
" \n",
" #To find the angular acceleration of the wheel\n",
"m=30 #units in Kg\n",
"k=0.25 #units in meters\n",
"I=m*k**2 #units in Kg meter**2\n",
"force=1.8 #units in Newtons\n",
"levelarm=0.40 #nits in meters\n",
"tou=force*levelarm #units in Newton meter\n",
"alpha=tou/I #units in rad/sec**2\n",
"print \"Angular acceleration is alpha=\",round(alpha,3),\" rad/sec**2\"\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex8.3:pg-242"
]
},
{
"cell_type": "code",
"execution_count": 10,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The time taken is t= 15.7 sec\n",
"\n",
"The wheel goes a distance of theta= 98.7 rad\n",
"\n",
"The rotational kinetic energy is KE= 197.0 Joules\n"
]
}
],
"source": [
" #Example 8_3\n",
" \n",
" \n",
" #To find out how long does it take to accelerate and how far does wheel turn in this time and the rotational kinetic energy\n",
"force=8 #units in Newtons\n",
"arm=0.25 #units in meters\n",
"tou=force*arm #units in Newton meter\n",
"m=80 #units in Kg\n",
"b=arm #units in meters\n",
"I=0.5*m*b**2 #units in Kg meter**2\n",
"alpha=tou/I #units in rad/sec**2\n",
"wf=4*math.pi #units in rad/sec\n",
"w0=0 #units in rad/sec\n",
"t=(wf-w0)/alpha #units in sec\n",
"print \"The time taken is t=\",round(t,1),\" sec\\n\"\n",
"theta=0.5*(wf+w0)*t #units in radians\n",
"print \"The wheel goes a distance of theta=\",round(theta,1),\" rad\\n\"\n",
"KE=0.5*I*wf**2 #units in Joules\n",
"print \"The rotational kinetic energy is KE=\",round(KE),\" Joules\"\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex8.4:pg-243"
]
},
{
"cell_type": "code",
"execution_count": 11,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The angular acceleration is alpha= 1.37 rad/sec**2\n",
"\n",
"The objects goes a distance of y= 51.4 meters\n"
]
}
],
"source": [
" #Example 8_4\n",
" \n",
" \n",
" #To find out the angular acceleration and the distance the object falls\n",
"f1=29.4 #units in Newtons\n",
"r1=0.75 #units in meters\n",
"m1=40 #units in Kgs\n",
"r2=0.6 #units in meters\n",
"m2=3 #units in Kgs\n",
"alpha=(f1*r1)/((m1*r2**2)+(m2*r1**2)) #units in rad/sec**2\n",
"print \"The angular acceleration is alpha=\",round(alpha,2),\" rad/sec**2\\n\"\n",
"a=r1*alpha #units in meters/sec**2\n",
"t=10 #units in sec\n",
"y=0.5*a*t**2 #units in meters\n",
"print \"The objects goes a distance of y=\",round(y,1),\" meters\"\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex8.5:pg-244"
]
},
{
"cell_type": "code",
"execution_count": 12,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The object is moving at v= 1.28 meters/sec\n"
]
}
],
"source": [
" #Example 8_5\n",
" \n",
" \n",
" #To find the speed of the object\n",
"m=3 #units in Kg\n",
"g=9.8 #units in meters/sec**2\n",
"h=0.80 #units in meters\n",
"m1=3 #units in Kg\n",
"m2=14.4 #units in Kg\n",
"r=0.75 #units in meters\n",
"v=sqrt((m*g*h)/((0.5*m1)+((0.5*m2)/r**2)))\n",
"print \"The object is moving at v=\",round(v,2),\" meters/sec\"\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex8.8:pg-247"
]
},
{
"cell_type": "code",
"execution_count": 15,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The sun would take for one revolution in time=\n",
"0.000216 sec\n"
]
}
],
"source": [
" #Example 8_8\n",
" \n",
" \n",
" #To find out how long does the sun take to complete one revolution\n",
"ra_rb=10.0**5\n",
"noofrev=1.0/25 #units in rev/day\n",
"wafter=(ra_rb)**2*(noofrev)\n",
"t=86400 #units in sec\n",
"time=t/wafter #units in sec\n",
"print \"The sun would take for one revolution in time=\"\n",
"print time,\"sec\"\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex8.9:pg-248"
]
},
{
"cell_type": "code",
"execution_count": 16,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The rotational speed is Wf= 1.63 rev/sec\n"
]
}
],
"source": [
" #Example 8_9\n",
" \n",
" \n",
" #To find out the rotational speed \n",
"m=0.3 #units in Kg\n",
"r=0.035 #units in meters\n",
"Iw=0.5*m*r**2 #units in Kg meter**2\n",
"Ibt=8*10**-4 #units in Kg meter**2\n",
"w0=2 #units in rev/sec\n",
"wf=(Ibt*w0)/(Ibt+Iw) #units in rev/sec\n",
"print \"The rotational speed is Wf=\",round(wf,2),\" rev/sec\"\n"
]
}
],
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|
