Problem with solving a program involving radians in `math` module

Question

I found a python question and facing trouble in solving it correctly.

The question is as follows.

In this problem, you're going to use that class to calculate the net force from a list of forces.

Write a function called find_net_force. find_net_force should have one parameter: a list of instances of Force. The function should return a new instance of Force with the total net magnitude and net angle as the values for its magnitude and angle attributes.

As a reminder:

• To find the magnitude of the net force, sum all the horizontal components and sum all the vertical components. The net force is the square root of the sum of the squares of the horizontal forces and the vertical forces (i.e.(total_horizontal2 + total_vertical2)0.5)
• To find the angle of the net force, call atan2 with two arguments: the total vertical and total horizontal forces (in that order). Remember to round both the magnitude and direction to one decimal place. This can be done using round(magnitude, 1) and round(angle, 1).
• The Force class has three methods: get_horizontal returns a single force's horizontal component. get_vertical returns a single force's vertical component. get_angle returns a single force's angle in degrees (or in radians if you call get_angle(use_degrees=False).
• HINT: Don't overcomplicate this. The Force class does a lot of functions except atan2, degrees, and radians.

I tried using the following code to solve it and am getting a different result for the get_angle. I tried changing things with radians, degrees with no correct result.

from math import atan2, degrees, radians, sin, cos

class Force:

    def __init__(self, magnitude, angle):
        self.magnitude = magnitude
        self.angle = radians(angle)

    def get_horizontal(self):
        return self.magnitude * cos(self.angle)

    def get_vertical(self):
        return self.magnitude * sin(self.angle)

    def get_angle(self, use_degrees = True):
        if use_degrees:
            return degrees(self.angle)
        else:
            return self.angle

def find_net_force(force_instances):
    total_horizontal = 0
    total_vertical = 0
    for instance in force_instances:
        total_horizontal += float(instance.get_horizontal())
        total_vertical += float(instance.get_vertical())
    net_force = round((total_horizontal ** 2 + total_vertical ** 2) ** 0.5, 1)
    net_angle = round(atan2(total_vertical, total_horizontal), 1)
    total_force = Force(net_force, net_angle)
    return total_force

force_1 = Force(50, 90)
force_2 = Force(75, -90)
force_3 = Force(100, 0)
forces = [force_1, force_2, force_3]
net_force = find_net_force(forces)
print(net_force.magnitude)
print(net_force.get_angle())

The expected output is:

103.1
-14.0

The actual result I got is:

103.1
-0.2

Update:

Thanks to Michael O. The class was expecting degrees and the function find_net_force was sending the angle in radians. I tried using the conversion to degrees in the find_net_force and it worked.

net_angle = round(degrees(atan2(total_vertical, total_horizontal)), 1)

Answer 1

Thanks to Michael O for helping out in the comments. The class was expecting degrees and the function find_net_force was sending the angle in radians.I tried using the conversion to degrees in the find_net_force and it worked.

net_angle = round(degrees(atan2(total_vertical, total_horizontal)), 1)