Center of Mass System

This interactive simulator explores Center of Mass System in Classical Mechanics. 2–4 bodies or rod: R_cm, V_cm; explosion with ΣΔp = 0; |P| and |V_cm| graphs. Use the controls to change the scenario; watch the visualization and any graphs or readouts to connect the model with lectures, labs, and homework.

Who it's for: Best once you already know the basic definitions and want to build intuition. Typical context: Classical Mechanics.

Key terms

  • center
  • mass
  • system
  • center of mass system
  • mechanics
  • classical

Live graphs

How it works

Several point masses (or two on a massless rod) move in a frictionless box. The center of mass and V_cm are drawn; total momentum and |V_cm| stay constant when you apply the symmetric internal “explosion” (ΣΔp = 0). Elastic walls change individual momenta but not P_tot.

Key equations

R_cm = Σmᵢrᵢ / Σmᵢ,   P = Σmᵢvᵢ = M_tot V_cm
Explosion: Δp_k = P(cos θ_k, sin θ_k), θ_k = 2πk/n + const ⇒ Σ_k Δp_k = 0