title: Ball falling plot of position over time with python
body: <p>I am trying to write a code that will plot the the simulation of a ball being dropped from a height h and make a graph of the position over time using the kinematic equations y = y_0 
  My code is this:</p>
  
  <p>from matplotlib.pylab import show, xlabel, ylabel, scatter, plot
  from numpy import empty</p>
  
  <pre><code>def drop():
  
      """
      This function calculates and creates arrays for the velocity at eac time interval as well as the position and plots it. Assuming no drag. 
      """
      #Define the constants in the problem
      h_0 = 10
      g = -9.8 #gravitational constant N
      dt = 0.1 #timestep
  
      #Now need to create arrays to hold the positins, time, and velocities
      vel = empty(1000,float)
      time = empty(1000,float)
      y = empty(1000,float)
  
      time[0] = 0
      vel[0] = 0
      y[0] = h_0
  
      #code for the kinematic equations for the calculation of time, velocity and position
      for i in range of (1000-1):
          time[i+1] = time[i] + dt
          vel[i+1] = vel[i] + (g * dt)
          y[i+1] = time[i] + (vel[i+1] * dt)
  
          if y[i] &gt; 0:
          #ensures that the graph will not keep going when the ball hits the ground
              break
  
  
      plot(time,y, '.')
      xlabel("Time(s)")
      ylabel("Position")
      show()
  </code></pre>
  
  <p>However my graph plots three dots one in each corner of the graph when it is supposed to look like a curve, and my graph changes every time which it shouldn't since none of the variables are changing</p>