One dimensional simulation of a falling object

gravitysim.py

#One dimensional gravity simulation.
#Programmed by Evan Weinberg
#v0.1 - Initial program

initial_height = 30 #meters
initial_velocity = 10 #m/s
mass = 1 #kilogram
g = 9.81 #m/s^2

is_ground = True #Set this to True if you want to simulate the ground.
is_there_air_resistance = True #Set this to True to turn on air resistance.
air_resistance_coefficient = 0.1 #N*s^2/m^2

steps = 50 #This is how many data points you want to collect
total_time = 5 #seconds
print_data = True

#Simulation data
delta_t = total_time*1./(steps*10)
current_t = 0
current_y = initial_height
current_v = initial_velocity
i = 0

data = []
data.append([current_t,current_y,current_v])

def is_air_resistance(is_there_air_resistance):
    if is_there_air_resistance == True:
        return 1
    else:
        return 0

def sgn(x):
    if(x >0):
        return 1
    else:
        return -1
    

while(current_t < total_time):
    current_t+=delta_t
    
    accel = 1./mass*(-mass*g-is_air_resistance(is_there_air_resistance)*air_resistance_coefficient*sgn(data[i][2])*data[i][2]**2)
    
    v = data[i][2]+accel*delta_t

    y = data[i][1] + data[i][2]*delta_t+0.5*accel*delta_t**2

    if(y<0 and is_ground == True):
        y = 0
        
    data.append([current_t,y,v])
    i = i + 1

    #print 't = %s, x = %s, v = %s'%(str(current_t), str(y), str(v))

print "Completed calculations."

outFile = open('gravitysim.txt','w')
count = 0
for row in data:
    
   
   if(count==0):
       count = 0
       new_t = row[0]
       new_y = row[1]
       output = str(new_t)+','+str(new_y)+'\n'
       outFile.write(output)
       if(print_data == True):
           print (output)
   count+=1
   if(count ==9):
       count = 0
    
outFile.close()