This is one of many models students can build to extend their understanding of Newton's second law.
Students first input forces to get the elevator moving up with an initial acceleration and then constant
velocity. Later problems involve getting the elevator to stop at an upper floor and finally getting the
elevator to return to the bottom floor. Students use an input graph to control the tension in the cable.
Vensim Version 
STELLA Version

[Diagram Level  Equations Level  Graphs ]
Displacement(t) = Displacement(t  dt) + (Rate_of_change_of_Displacement) * dt
INIT Displacement = 0
Rate_of_change_of_Displacement = Velocity
Velocity(t) = Velocity(t  dt) + (Rate_of_change_of_Velocity) * dt
INIT Velocity = 0
Rate_of_change_of_Velocity = Acceleration
Acceleration = Net_force/mass
acceleration_due_to_gravity = 9.8 {m/s^2}
Applied_force = tension
mass = 1000 {kg}
Net_force = Applied_force+Opposing_force
Opposing_force = Weight
Weight = mass*acceleration_due_to_gravity
tension = GRAPH(time)
(0.00, 10000), (1.00, 10000), (2.00, 10000), (3.00, 9800), (4.00, 9800), (5.00, 9800), (6.00, 9800), (7.00, 9800), (8.00, 9800), (9.00, 9800), (10.0, 9800), (11.0, 9800), (12.0, 9800)
Time Specs Settings
Standard: Range: 012; dt = 0.25; Integration Method = Euler's
