The masses and coordinates of three spheres are as follows: 28 kg, x = 1.00 m, y = 2.50 m; 44 kg, x = -2.00 m, y = -1.75 m; 54 kg, x = 0.00 m, y= -0.50 m. What is the magnitude of the gravitational force on a 18 kg sphere located at the origin due to the other spheres?

better_gravity.py

import math
 
G = 6.67e-11

class Point:
    def __init__(self,m,x,y):
        self.m = m
        self.x = x
        self.y = y

    def force(self,m):
	return (G*self.m*m)/(math.pow(self.x,2)+math.pow(self.y,2))

    def xD(self,m):
        return self.component(m, self.x, math.cos)

    def yD(self,m):
        return self.component(m, self.y, math.sin)

    def component(self,m,driving,f):
	direction = ((-2 * (driving < 0)) + 1) * self.force(m)
	try:
		return direction *f(math.atan(self.y/self.x))
	except:
		return direction *f(math.pi/2)

a = Point(28,1,2.5)
b = Point(44,-2,-1.75)
c = Point(54,0,-0.50)
 
m = 18
  
fx = a.xD(m) + b.xD(m) + c.xD(m)
fy = a.yD(m) + b.yD(m) + c.yD(m)
 
print math.sqrt(math.pow(fx,2) + math.pow(fy,2))

gravity.py

import math

def force(m1,m2,r1,r2):
	return (G*m1*m2)/(math.pow(r1,2)+math.pow(r2,2))

def x(f,r1,r2):
	try:
		magnitude = f*math.cos(math.atan(r2/r1))
	except:
		magnitude = f*math.cos(math.pi/2)
	direction = 1 if (r1==0) else (math.fabs(r1)/r1)
	return magnitude*direction

def y(f,r1,r2):
	try:
		magnitude = f*math.sin(math.atan(r2/r1))
	except:
		magnitude = f*math.sin(math.pi/2)
	direction = 1 if (r2==0) else (math.fabs(r2)/r2)
	return magnitude*direction

G = 6.67e-11

m1		= 28
m1r1 	= 1
m1r2 	= 2.5

m2		= 44
m2r1 	= -2
m2r2 	= -1.75

m3		= 54
m3r1 	= 0
m3r2 	= -0.50

m 		= 18

f1 = force(m1,m,m1r1,m1r2)
f2 = force(m2,m,m2r1,m2r2)
f3 = force(m3,m,m3r1,m3r2)

fx = x(f1,m1r2,m1r1) + x(f2,m2r2,m2r1) + x(f3,m3r2,m3r1)
fy = y(f1,m1r2,m1r1) + y(f2,m2r2,m2r1) + y(f3,m3r2,m3r1)

print math.sqrt(math.pow(fx,2) + math.pow(fy,2))

Woah white space got funky during the declaration