Falling: 5 metres in the first second

A dropped object falls ~5 m in the first second and gains ~10 m/s of speed every second.

Why it works

d = ½gt² with g ≈ 9.8 m/s². Two seconds ≈ 20 m — a quick way to depth-sound a well or cliff with a stone.

Do it exactly

Estimate with the rule, then check it against the calculator that models it properly.

Open Galileo Drop Experiment →

More in Physics Simulation

• ζ = 1 is critical dampingWhen the damping ratio hits 1, the system returns to rest as fast as possible without overshoot …
• A metre swings in two secondsA 1 m pendulum takes almost exactly 2 s per full swing.
• Pendulum period: √length, not massQuadruple a pendulum’s length and it swings half as fast. Mass doesn’t matter at all.
• 45° for range — in a vacuumWithout air drag, 45° maximizes projectile range; with drag, the real optimum is nearer 30–40°.

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