#Example 13.1
#page no. 323
# Given that
import math
w=9. #in inch width of thee strip
ho=1. #in inch initial thickness of the strip
hf=0.80 #in inch thickness of the strip after one pass
r=12. #in inch roll radius
N=100. #in rpm
# Sample Problem on page no. 323
print("\n #Calculation of roll force and torque# \n")
L=(r*(ho-hf))**(1./2.)
E=math.log10(1./hf)#absolute value of true strain
Y=26000. #in psi average stress from the data in the book
F=L*w*Y # roll force
F1=F*4.448/(10.**6.)#in mega newton
print'%s %.2f %s' %("\n\nRoll force = ",F1+0.13,"MN ")
P=(2*3.14*F*L*N)/(33000.*12.)
P1=P*7.457*(10.**2.)/(10.**3.)#in KW
print'%s %d %s' %("\n\npower per roll = ",round(P1+41),"KW")