Learn Encapsulation by Building a Projectile Trajectory Calculator - Step 6

Python
1

Tell us what’s happening:

What am i missing here? The results of the test are looking good:

The method should return the correct value. For Projectile(12, 12, 12), given the 4 $x$ coordinates of 0, 1, 2 and 3, the y coordinate should be approximately 12, 12.18, 12.28, 12.32.

Your code so far

import math

GRAVITATIONAL_ACCELERATION = 9.81
PROJECTILE = "∙"
x_axis_tick = "T"
y_axis_tick = "⊣"

class Projectile:
    __slots__ = ('__speed', '__height', '__angle')

    def __init__(self, speed, height, angle):
        self.__speed = speed
        self.__height = height
        self.__angle = math.radians(angle)
        
    def __str__(self):
        return f'''
Projectile details:
speed: {self.__speed} m/s
height: {self.__height} m
angle: {round(math.degrees(self.__angle))}°
displacement: {round(self.__calculate_displacement(), 1)} m
'''

    def __calculate_displacement(self):
        horizontal_component = self.__speed * math.cos(self.__angle)
        vertical_component = self.__speed * math.sin(self.__angle)
        squared_component = vertical_component**2
        gh_component = 2 * GRAVITATIONAL_ACCELERATION * self.__height
        sqrt_component = math.sqrt(squared_component + gh_component)
        
        return horizontal_component * (vertical_component + sqrt_component) / GRAVITATIONAL_ACCELERATION
        

# User Editable Region

    def __calculate_y_coordinate(self, x):
        y = self.__height + x * math.tan(self.__angle) - ((GRAVITATIONAL_ACCELERATION * x**2) / (2 * self.__speed**2 * math.cos(self.__angle)))
        return y

# User Editable Region


ball = Projectile(12, 12, 12)
print(ball)
print(ball._Projectile__calculate_y_coordinate(2))

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Challenge Information:

Learn Encapsulation by Building a Projectile Trajectory Calculator - Step 6

2

It looks like you are missing a square in the last part of the equation (cosine)

3

Oh, my. Thank you! Maybe it was already too late yesterday :smiley:

1 Like
4

Pretty easy to miss and your answers were already close :+1:

5

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