This simulator ports the projectile-motion kinematics (s = v0t + ½at²) and the elastic-collision formula (v1' = ((m1-m2)v1 + 2m2v2) / (m1+m2)) from their original 2D calculator form into a genuine 3D scene: a launcher fires a sphere along a true parabolic arc through adjustable gravity, elevation and azimuth, and when it strikes a second, resting sphere, the exact vector generalization of that elastic collision formula computes both bodies' outgoing velocities. Momentum and kinetic energy readouts before and after impact let you verify conservation directly, and a full drag-to-orbit, scroll-to-zoom camera lets you inspect the trajectory and impact from any angle.
Adjust launch speed, elevation and azimuth to aim the shot, dial gravity between lunar, Martian and terrestrial values, set the projectile and target masses, and place the target at any distance before firing. After the collision both spheres keep falling under gravity until they land, so you can watch the full energy story play out from launch to rest.