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{
"metadata": {
"name": "",
"signature": "sha256:7b15e8f180333ee46bf2dbf70747d7d301a3bed09a0eb6d2a0ced67423d0f6af"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 10:Principles of Lifting Machines"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 10.1, Page no.173"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"W=1000 #Weight in N\n",
"P=25 #Effort in N\n",
"x=0.1 #Distance through which the weight is moved in m\n",
"y=8 #Distance through which effort is moved in m\n",
"\n",
"#calculation\n",
"MA=W/P\n",
"VR=y/x\n",
"Eta=MA/VR\n",
"\n",
"#Result\n",
"print\"Mechanical advantage of the machine, M.A.=\",int(MA)\n",
"print\"Velocity ratio of the machine, V.R.=\",int(VR)\n",
"print\"Efficiency of the machine, Eta=\",int(round(Eta*100,1)),\"%\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Mechanical advantage of the machine, M.A.= 40\n",
"Velocity ratio of the machine, V.R.= 80\n",
"Efficiency of the machine, Eta= 50 %\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 10.2, Page no.174 "
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"VR=30 #Velocity ratio\n",
"W=1500.0 #Load in N\n",
"P=125 #Effort in N\n",
"\n",
"#calculation\n",
"MA=W/P\n",
"Eta=MA/VR\n",
"\n",
"#Result\n",
"print\"Efficiency, Eta=\",int(round(Eta*100,1)),\"%\"\n",
"print\"Since efficiency of the machine is less than 50%, therefore the machine is non-reversible\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Efficiency, Eta= 40 %\n",
"Since efficiency of the machine is less than 50%, therefore the machine is non-reversible\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 10.4, Page no.176"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"P=100.0 #Effort in N\n",
"W=840.0 #Load in N\n",
"VR=10 #vecocity ratio\n",
"\n",
"#calculation\n",
"#To calculate efficiency of the machine\n",
"MA=W/P\n",
"Eta=(MA/VR)*100\n",
"#To calculate friction of the machine\n",
"F_effort=P-(W/VR) #In terms of effort\n",
"F_load=(P*VR)-W #In terms of load\n",
"\n",
"#Result\n",
"print\"Efficiency of the machine, Eta=\",int(Eta),\"%\"\n",
"print\"Friction of the machine in terms of effort, F_effort=\",int(F_effort),\"N\"\n",
"print\"Friction of the machine in terms of load, F_load=\",int(F_load),\"N\"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Efficiency of the machine, Eta= 84 %\n",
"Friction of the machine in terms of effort, F_effort= 16 N\n",
"Friction of the machine in terms of load, F_load= 160 N\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 10.9, Page no.181"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"m=0.02 #On dividing W/50 we get 0.02W where m=0.02\n",
"W=600 #Load in N\n",
"VR=100 #velocity ratio\n",
"\n",
"#calculation\n",
"Max_MA=1/m\n",
"Max_Pos_Efficiency=1/(m*VR)\n",
"P=m*W+8 #Given\n",
"F_effort=P-(W/VR)\n",
"MA=W/P\n",
"Eta=MA/VR\n",
"\n",
"#Result\n",
"print\"Maximum possible mechanical advantage, Max M.A.=\",int(Max_MA)\n",
"print\"Maximum possible efficiency=\",int(round(Max_Pos_Efficiency*100,1)),\"%\"\n",
"print\"Effort required to overcome the machine friction, F_effort=\",int(F_effort),\"N\"\n",
"print\"Efficiency of the machine, Eta=\",int(round(Eta*100,1)),\"%\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Maximum possible mechanical advantage, Max M.A.= 50\n",
"Maximum possible efficiency= 50 %\n",
"Effort required to overcome the machine friction, F_effort= 14 N\n",
"Efficiency of the machine, Eta= 30 %\n"
]
}
],
"prompt_number": 12
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}
|
