find net force

from math import sin, cos, tan, asin, acos, atan2, radians, degrees, sqrt

def find_net_force_from_file(filename):
    total_horizontal = 0
    total_vertical = 0
    forces=[]
    mtr=open(filename,"r")
    forces=mtr.readlines()
    forces = [i.split(' ') for i in forces] 
    #Now, let's iterate through each force in the forces:
    for force in forces:
        
        #To make our code easier to read, let's pull the
        #magnitude and angle out from the tuple:        
        magnitude, angle = force
        
        #The directions told us we need to convert our
        #angles to radians to use Python's trignometric
        #functions:
        angle = radians(float(angle))
        
        #Now, the horizontal component is the magnitude
        #times the cosine of the angle:
        horizontal = int(magnitude) * (cos(angle))
        
        #And the vertical component is the magnitude times
        #the sine of the angle:
        vertical = int(magnitude) * sin(angle)
        
        #Now that we've calculated the horizontal and
        #vertical components, let's add those to our
        #running tallies:
        total_horizontal += horizontal
        total_vertical += vertical
    
    #The net magnitude is the hypotenuse of the triangle
    #with these two components as their legs. So, we can
    #calculate the net magnitude using the Pythagorean
    #theorem:
    net_magnitude = sqrt(total_horizontal**2 + total_vertical**2)
    
    #Then as instructed, we round it to one decimal point:
    net_magnitude = round(net_magnitude, 1)
    
    #Next, we need to calculate the angle. As directed, we
    #do this with the atan2 function from Python's math
    #library, which takes the vertical and horizontal
    #components as arguments:
    net_angle = atan2(total_vertical, total_horizontal)
    
    #Then, we convert this back to degrees:
    net_angle = degrees(net_angle)
    
    #And round it to one decimal point as instructed:
    net_angle = round(net_angle, 1)
    mtr.close()
    #Last, we return the tuple of the madnitude and angle:
    return (net_magnitude, net_angle)