old_contents: ### Import our stuff
  import matplotlib.pyplot as plt
  import numpy as np
  import pandas as pd
  
  ### Set up initial values
  position = 555 # feet
  velocity = 0 # feet/second
  acceleration = -32.17 # feet / second^2
  time_steps = np.linspace(0, 5, 501) # creates two entries at time zero
  time_step_size = time_steps[1] - time_steps[0]
  
  ### Create a way to collect/record data
  initial_data = {
      'position': [position, 12],
      'velocity': [velocity],
      'acceleration': [acceleration],
      'time': [0]
  }
  
  motion_data = pd.DataFrame(initial_data)
  
  ### Evolve the simulation forward using our update rules
  
  for time_step in time_steps:
      velocity = velocity + (acceleration * time_step_size)
      position = position + (velocity * time_step_size)
      
      updated_data = pd.DataFrame({
          'position': [position],
          'velocity': [velocity],
          'acceleration': [acceleration],
          'time': [time_step]
      })
      motion_data = motion_data.append(updated_data)
  
  motion_data.plot.line(
      x = 'time',
      y = 'position'
  )
  
  motion_data
      
  
  
  
  
new_contents: ### Import our stuff
  import matplotlib.pyplot as plt
  import numpy as np
  import pandas as pd
  
  ### Set up initial values
  position = 555 # feet
  velocity = 0 # feet/second
  acceleration = -32.17 # feet / second^2
  time_steps = np.linspace(0, 5, 501) # creates two entries at time zero
  time_step_size = time_steps[1] - time_steps[0]
  
  ### Create a way to collect/record data
  initial_data = {
      'position': [position],
      'velocity': [velocity],
      'acceleration': [acceleration],
      'time': [0]
  }
  
  motion_data = pd.DataFrame(initial_data)
  
  ### Evolve the simulation forward using our update rules
  
  for time_step in time_steps:
      velocity = velocity + (acceleration * time_step_size)
      position = position + (velocity * time_step_size)
      
      updated_data = pd.DataFrame({
          'position': [position],
          'velocity': [velocity],
          'acceleration': [acceleration],
          'time': [time_step]
      })
      motion_data = motion_data.append(updated_data)
  
  motion_data.plot.line(
      x = 'time',
      y = 'position'
  )
  
  motion_data
      
  
  
  
  
subject: Remove dataframe error we were testing