Return to Web Labs at


This system has a pivot and a weight ("bob") at the end of a rigid, massless rod of 1 meter length. The green vector is tangential linear velocity. The blue vectors are components of acceleration. The dotted blue vector is the constant gravitational acceleration. Friction at the pivot is proportional to velocity. The simulation runs in slow motion. More info

Click the Run button to start. Hit the enter key or click out of field after changing inputs.

simulation time (s):


initial tangential velocity (m/s):

start angle (-180° to 180°):

friction factor (dimensionless):