Bouncing Bob Pendulum

mass ratio

0.58

length ratio

0.9

rebound ratio

0.85

initial position bob 1

60°

initial position bob 2

40°

show trace bob 2

type of plot

position

speed

energy

animation

E

k

U

E

t

This Demonstration simulates the motion of a double pendulum with the upper bob bouncing back from an obstruction along the vertical axis.

Mathematica's built-in function WhenEvent, triggered whenever the upper bob crosses the vertical, reverses and reduces the angular speed of the upper pendulum and changes the behavior of the lower pendulum accordingly.