Free Fall Calculator

In short An object dropped from 100 m takes 4.516 seconds to fall and lands at 44.29 m/s, which is 159.4 km/h. The time is √(2h/g) and the impact speed is √(2gh) — and the mass appears in neither, which is Galileo's result and the reason a hammer and a feather land together on the Moon. This page computes the impact speed two separate ways and prints both: once from the kinematic equations, and once from conservation of energy, where mgh = ½mv² and the mass cancels algebraically. They share no working, so agreement is a check rather than a restatement. A useful anchor is that anything falls 4.903 m in the first second — the g/2 term — and the distance grows with the square of time, so it covers three times that in the second second. The critical limitation is air. Every figure here assumes a vacuum, and the error grows without limit: a human reaches terminal velocity in around 12 seconds and roughly 450 m, after which the real speed stops rising while this page keeps adding 9.8 m/s every second. For short drops of dense objects the vacuum answer is close; for anything longer, use the terminal velocity page instead, where speed approaches a ceiling rather than growing forever.