# Chapter 5 : Force Analysis of Structures¶

## Example 5.1 Page No : 98¶

In [10]:

import math
# Variables
Fc = -1000. 			#lb
A = 60. 			#degrees
E1 = 60. 			#degrees
E2 = 60. 			#degrees
D = 60. 			#degrees
L1 = 10. 			#ft
L2 = 10. 			#ft

# Calculations
Ax = 0
Ay = (-Fc)*L1*math.cos(math.radians(D))/(L1+L2)
Dy = -Fc-Ay
Fab = Ay/math.sin(math.radians(A))
Fae = Fab*math.cos(math.radians(A))
Fbe = Fab*math.cos(90-E1)/math.cos(90-A)
Fbc = Fab*math.sin(math.radians(90-A))+Fbe*math.sin(math.radians(90-E1))
Fce = Fbc*math.cos(90-(180-E2-D))/math.cos(90-E2)
Fde = Fae+Fbe*math.cos(math.radians(E1))+Fce*math.cos(math.radians(E2))
Fcd = (-Fc-Fbc*math.cos(math.radians(90-E2-D)))/math.cos(math.radians(90-E1))

# Results
print  'Ax = %.3f lb'%(Ax)
print  'Ay = %.2f lb'%(Ay)
print  'Dy = %.3f lb'%(Dy)
print  'Fab = %.1f lbcompression'%(Fab)
print  'Fae = %.1f lbtension'%(Fae)
print  'Fbe = %.1f lbtension'%(Fbe)
print  'Fbc = %.1f lbcompression'%(Fbc)
print  'Fce = %.1f lbcompression'%(Fce)
print  'Fde = %.1f lbtension'%(Fde)
print  'Fcd = %.1f lbcompression'%(Fcd)

Ax = 0.000 lb
Ay = 250.00 lb
Dy = 750.000 lb
Fab = 288.7 lbcompression
Fae = 144.3 lbtension
Fbe = 288.7 lbtension
Fbc = 288.7 lbcompression
Fce = 288.7 lbcompression
Fde = 433.0 lbtension
Fcd = 866.0 lbcompression


## Example 5.2 Page No : 103¶

In [2]:

# Variables
W = -100. 			#lb
angle = 45. 			#degrees
x1 = 2. 			#ft
x2 = 2. 			#ft
y1 = 2. 			#ft
y2 = 4. 			#ft
Fx = 200. 			#lb

# Calculations
Cx = Fx*y1/y2
Bx = Fx+Cx
By = (y2*Bx+x1*(-W))/(x1+x2)
Cy = By
Ax = Bx
Ay = W+By

# Results
print  'Ax = %.3f lb'%(Ax)
print  'Ay = %.2f lb'%(Ay)
print  'Bx = %.3f lb'%(Bx)
print  'By = %.2f lb'%(By)
print  'Cx = %.2f lb'%(Cx)
print  'Cy = %.2f lb'%(Cy)

Ax = 300.000 lb
Ay = 250.00 lb
Bx = 300.000 lb
By = 350.00 lb
Cx = 100.00 lb
Cy = 350.00 lb