Chapter_3: Force Torque and Velocity

Example 3.1, Page Number: 163

In [6]:
#variable declaration
m1=20                       #mass of the body in Kg
a=5                         #acceleration in m/s^2

#calculation
F=m1*a

#result
print('F = %d Newtons'%F)

F = 100 Newtons

Example 3.2, Page Number: 163

In [7]:
#variable declaration
m1=50                      #mass of the body in Kg
g1=9.8                     #acceleration due to gravity

#calculation
W2=m1*g1

#result
print('W = %d Newtons = %d kgf' %(W2,m1))

W = 490 Newtons = 50 kgf

Example 3.3, Page Number: 164

In [8]:
#variable declaration
wt_material=2500.0         #weight of 1 m^3 material
wt_water=1000.0            #weight of 1 m^3 water

#calculation
spe_grav=wt_material/wt_water

#result
print('Specific gravity of the material = %.1f' %spe_grav)

Specific gravity of the material = 2.5

Example 3.4, Page Number: 164

In [9]:
import math
#variable declaration
L=20.0                     # length in cm
W=2000.0                   # Weight of mass in gm
db=0.02                    # length in cm
Wb=100.0                   # Weight of mass in gm
dG=0.5                     # length in cm

#calculation
S=L/(2*W*db+Wb*dG)
fi=0.2
DeltaW=fi*math.pi/(180*S)

#result
print('\nDeltaW = %.3f g' %DeltaW)

S = 0.154 rad/g

DeltaW = 0.023 g

Example 3.5, Page Number: 164

In [10]:
import math

#variable declaration
hp=746.0                   # horse power
P=5*hp                     # Saft power in Watts
N=1500.0                   # speed in rpm

#calculation
n=N/60.0
T=P*60/(2*math.pi*n)

#result
print('T = %.0f Newton meters' %(math.ceil(T)))

T = 1425 Newton meters

Example 3.6, Page Number: 165

In [11]:
#variable declaration
ch_l=0.075               #change in length
orig_l=50.0              #Original length

#calculation
S=ch_l/orig_l
E=9.66*10**5
stress=E*S
area=1.5
f=stress*area

#result
print('Strain = %.4f cm/cm\nStress =%d kg/cm^2\nForce = %.1f kg'%(S,stress,f))

Strain = 0.0015 cm/cm
Stress =1449 kg/cm^2
Force = 2173.5 kg

Example 3.7, Page Number: 165

In [12]:
import math

#(a)

#variable declaration
R1=120.0                    # resistance in Ohm
R2=120.0                    # resistance in Ohm
R3=120.0                    # resistance in Ohm
R4=120.0                    # resistance in Ohm
Rg=100.0                    # resistance in Ohm

#calculation
C=(R1*R2*R4)+(R1*R3*R4)+(R1*R2*R3)+(R2*R3*R4)+(Rg*(R1+R4)*(R2+R3))
C=C/(10**7)

#result
print('(a)\nC=%.3f*10^7' %C)
E=10
F=(E*R3*R1*2*10**3)/(C*10**7)
print('\nF = %.1f *10^3 A/mm = %.1f mA/mm'%(F,F))

#(b)

#calculation
Fe=2*10**-4
E=10
DeltaE=Fe*E/(4+4*10**-4)
DeltaE=DeltaE*10**3

#Result
print('\n(b)\nDeltaEg=%.1f mV' %DeltaE)

(a)
C=1.267*10^7

F = 22.7 *10^3 A/mm = 22.7 mA/mm

(b)
DeltaEg=0.5 mV

Example 3.8, PAge Number: 167

In [13]:
#(a)
import math

#variable Declaration
r1=2500.0                       # Highest flasing rate
r2=1500.0                       # next Highest flasing rate

#calculation
n=(r1*r2)/(r1-r2)

#result
print('(a)\nn = %d rpm'%n)

#(b)

#variable declaration
N=5.0                         # Fift time syncronization for same speed

#calculation
r5=n*r1/((r1*(N-1))+n)
r5=math.ceil(r5)

#result
print('\n(b)\nr5=%d Flashes/Minute' %r5)

(a)
n = 3750 rpm

(b)
r5=682 Flashes/Minute

Example 3.9, Page Number: 167

In [14]:
#variable declaration
rpm=1500.0                   #rotation in rpm
f=200.0                      #frequency

#calculation
N=60*f/rpm

#result
print('No of teeth on the wheel\nN=%d' %N)

No of teeth on the wheel
N=8