Question

Write a function that plots the following trajectory equations using python turtle graphics.

x = v*sin(A)*t

y = v*cos(A)*t -.5*(9.8)*t**2

Loop through t starting at 0 and increment by .1 until y<=0. (hint, while loop) Experiment with values of velocity V (1 to 20) and angle A (0 to 90) that gives you a good plot that does not go off the screen. Position the start of the plot at the left bottom of the screen

Answer 1

import math

import turtle

#declare v,A as a global value

v = 20

A = math.radians(45)    #Convert the angle to radians

#define x and y as functions

def x_val(t):

    return v*math.sin(A)*t

def y_val(t):

    return v*math.cos(A)*t - 0.5*9.8*(t**2)

#driver code for printing

tS = turtle.Screen()    # open the turtle screen

tT = turtle.Turtle()    # initiate the turtle

t = 0

x_prev = 0              # prev value of x

x_curr = 0              # curr value of x

y_prev = 0              # prev value of y

y_curr = 0              # curr value of y

while y_curr >= 0.0:        # Untill y is not negative loop

                            # turtle by default is facing right

    tT.forward(x_curr - x_prev)    # use forword to displace by difference in positions

    tT.left(90)               # turn turtle upward

    tT.forward(y_curr-y_prev)    # update y direction

    tT.right(90)              # turn the turtle to face right for next update

    t += 0.1                # update the time

    x_prev = x_curr

    y_prev = y_curr

    x_curr = x_val(t)

    y_curr = y_val(t)           # update the x,y coordinates

turtle.done()