title: Python and physics - calculating drag & determining if object has reached terminal velocity
body: <p>I'm trying to calculate the drag of a sphere if it were to be dropped off a building, the program runs but the equations wrong. It could be that I'm just making this overly complexed, but I'm stuck right now.. What I am trying to do is determine the amount of distance the sphere has traveled in the allotted time (Which works), but I am unable to figure out a way to use drag as a factor. Any help would be appreciated</p>
  
  <pre><code>import math
  
  height = float(raw_input("Enter the height of the building: ")) #meters
  weight = float(raw_input("Enter the weight of the sphere: ")) #weight of sphere in kilograms
  mass = float(raw_input("Mass of the sphere: ")) #mass of the sphere
  time = float(raw_input("Enter the time interval: ")) #determines how long to continue the experiment after the sphere has been dropped
  
  # kilograms
  #variables
  velocity = math.sqrt(2) * height * weight #calculate the velocity
  energy = 1 / 2 * mass * velocity ** 2 #kinetic energy
  gravity = 9.81      #gravity
  radius = 0.5       #radius of the sphere being dropped
  volume = 4.3 * math.pi * radius ** 3 #calculate the volume
  speed = gravity * time #determine the maximum speed in the time allotted
  density = mass / volume #determine the density of the sphere
  force = mass * gravity  #determine the force in newtons 
  drag = gravity * density * speed ** 2 #calculate the drag
  distance = .5 * gravity * time ** 2 #calculate the distance traveled
  
  print "Force = {} Newtons".format(force)
  print "The ball is", height - distance, "meters from the ground"
  print "The maximum speed of the ball was:", speed
  print "It would take the ball {} seconds to reach terminal velocity"#.format(None)
  print "Density:", density
  print "Drag: ", drag
  print "Mass: ", mass
  print "Volume: ", volume
  print "Velocity: ", velocity
  </code></pre>