Python Syntax
The Main Idea
This page discusses basic vPython functions and how they can be used to produce a model. vPython uses the same syntax as regular Python; however, vPython also allows you to produce a 3D model simulating the equations and computations your code is producing.
Mathematical Model
Vpython can be used with any equation. However, you may find some of the following useful:
Momentum Update: pf = pi + Fnet*deltat
Position Update: objectf.pos = objecti.pos + (pcart/mcart)*deltat
Gravitational Force:
- CONSTANTS
G = 6.7e-11 mEarth = 6e24 mcraft = 15e3 deltat = 60 t = 0
r=craft.pos-Earth.pos #finds the change in position m=mcraft rmag= mag(r) #finds the magnitude of change in position Fmag=(G*mcraft*mEarth)/(rmag**2)
# ^^Calculates the new magnitude of gravitational force
rhat=r/rmag
#^^Calculates the direction of tbe change in position
Fnet=-Fmag*rhat
- ^^Calculates net force
Spring Force:
L0 = 0.3 Lvec = ball.pos - ceiling.pos Lhat = norm(Lvec) Lmag = mag(Lvec) Fspr = (-ks)*(Lmag - L0)*(Lhat)
Kinetic Energy:
Kinetic = (1/2)*(mball*(vel**2))
Computational Model
VPython is used to create computational models of various real world situations so that we can see how these equations used in the code can manipulate these situations.