1.5.A.sagews

from sympy.physics.units import *
from sympy import *

print("\n--- User input -----------------------")

symbolic = True
symbolic = False

if symbolic:
    # quantity = symbol:
    a, b, c = var("a, b, c")
    F, q = var("F, q")
else:
    # quantity =  factor times unit:
    (a, b, c) = (3*m, 4*m, 5*m)
    F = 5*newton
    q = S(6)/5*newton/m

print("\n--- a: -------------------------------")
R = c*q

pprint("R:")
pprint(R)

print("\n--- b: -------------------------------")
# Unknowns:
A_h, A_v, B = var("A_h A_v B")

pprint("Equilibrium conditions:")
eq1 = Eq(0, A_h + 3*B/5 - 3*R/5)
eq2 = Eq(0, F - A_v - 4*B/5 + 4*R/5)
eq3 = Eq(0, c*B - c/2*R + a*F - 2*a*A_v)

for eq in [eq1, eq2, eq3]:
    pprint(eq)

# solve for unknowns:
eqs = [eq1, eq2, eq3]
sol = solve(eqs, [A_h, A_v, B])
pprint("Solution:")
for s in sol:
    pprint("")
    pprint(s)
    pprint(sol[s])

--- User input ----------------------- --- a: ------------------------------- R: 6*kg*m ------ 2 s --- b: ------------------------------- Equilibrium conditions: 3*B 18*kg*m 0 = A_h + --- - ------- 5 2 5*s 4*B 49*kg*m 0 = -A_v - --- + ------- 5 2 5*s 0 = -6*A_v*m + 5*B*m Solution: A_h 0 A_v 5*kg*m ------ 2 s B 6*kg*m ------ 2 s