1D Kinematics: Free Fall

Free fall means the only force acting is gravity. Acceleration is constant at a = −g — always downward, always the same magnitude, whether the object moves up, down, or is momentarily at rest.

At the peak, velocity is instantaneously zero — but acceleration is still −g. The object does not pause; it reverses direction in a single instant. Watch the v(t) line cross zero without any kink — it is perfectly straight throughout the motion.

Symmetry (when y₀ = 0): time to reach the peak equals time to fall back. Impact speed equals launch speed. The trail dots are equally spaced in time — their unequal spacing in height shows that equal time intervals produce unequal displacements, the hallmark of constant acceleration. Use Strobe Mode to see this most clearly.

Gravity presets let you compare how the same launch behaves on different worlds. On the Moon (g = 1.6 m/s²), the object rises much higher and takes far longer to land — the v(t) slope is shallower because acceleration is weaker.