Collision Pendulum

DCS Code: 1N30.50 Last Updated: March 27, 2026
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Purpose

Two visually identical balls with different internal damping properties strike a wooden block from a pendulum. The "happy" ball rebounds elastically and knocks the block over; the "sad" ball dissipates its energy internally and barely moves the block. Dramatically demonstrates how elastic vs. inelastic collisions differ in momentum transfer.

Collision pendulum with aluminum vertical post, metal rod pivoting from top with dark ball attached, rectangular wooden block standing on a wooden base, second interchangeable ball in holder on the base
Figure 1: The collision pendulum with one ball attached and the spare ball on the base. The balls screw onto the rod and appear identical, but the "happy" ball rebounds while the "sad" ball does not.
Demo Apparatus