free falling object with air resistance?

Question

we already know that if we plot speed vs time of free falling object it will be y=gx graph because we know the acceleration is gravity.

If it have air-resistance acceleration will be change right?.

So how we can plot the speed vs time graph of free falling object with air resistance ?

It have some equations or not.

because i want to plot it by using python.

Thanks.

sorry about my english.

This picture i saw from google but i want to make it by coding

Answer 1

As you may (or may not) know drag is dependant on the square of velocity.

Have a read for a bit more information: http://en.wikipedia.org/wiki/Drag_%28physics%29

You can see it is also dependant on various properties of the object and the fluid it is travelling through. Changing the "coeff" parameter in the code below will change how the drag is modelled. As requested:

import numpy as np
import matplotlib.pyplot as plt

coeff=0.2

times = np.linspace(0,3.5,100)
tstep = (max(times)-min(times))/len(times)

no_drag_velocities = 9.8*times

a=0
v=0
drag_velocities = []
for i in times:
    drag_velocities.append(v)
    a=9.8-coeff*v**2*tstep
    v=v+a*tstep

plt.plot(times,no_drag_velocities,label="Without Drag") 
plt.plot(times,drag_velocities,label="With Drag")
plt.xlabel("Time [s]")
plt.ylabel("Speed [m/s]")
plt.legend(loc="upper left")
plt.grid()
plt.show()