Rocking Roly Poly Toy

​
starting angular position
40°
eccentricity of mass center
0.52
damping coefficient
0.1
animation
time
θ(t)
′
θ
(t) / 10
This Demonstration simulates the rocking motion of a Roly Poly toy.
This hollow toy is bottom weighted with its center of mass beneath its center of rotation. When pushed from its upright equilibrium position and released, it oscillates vertically. Because of frictional damping, it eventually moves back to its equilibrium position.

Details

The equilibrium of forces is expressed in the equation of motion
mgsinθ(t)+μ
′
θ
(t)+mrsinθ(t)
2
′
θ
(t)
+ma+
2
r
a
-2rcosθ(t)
′′
θ
(t)0
.

Permanent Citation

Erik Mahieu
​
​"Rocking Roly Poly Toy"​
​http://demonstrations.wolfram.com/RockingRolyPolyToy/​
​Wolfram Demonstrations Project​
​Published: August 8, 2013